Northeast India Research Articles

Rice Equivalent Yield and Soil Properties as Influenced by Conventional and Minimum Tillage System in Rice Based Cropping Sequence in North-East India

Rice Equivalent Yield and Soil Properties as Influenced by Conventional and Minimum Tillage System in Rice Based Cropping Sequence in North-East India

Marital violence affects reproductive health and pregnancy outcomes in Northeast India.

As per the National Family Health Survey (NFHS-4, 2015-16) report, 40% of women aged 15-49 in India experienced intimate partner violence (IPV), with emotional abuse significantly associated with negative reproductive health (RH) outcomes. The study uses secondary data from the NFHS-4 and conducts statistical analysis based on information gathered from 8766 married women aged 15-49years in Northeast India. Bivariate analysis followed by multiple logistic regression analysis is performed to understand the relationship between IPV and its effects on women's RH. The findings indicate that ever-married women in Northeast India have faced physical violence (25.1%), sexual violence (11.8%), emotional abuse (6.4%) and severe violence (5.3%). Among all women who participated in the study, 6.9% had experienced non-live births, 4.2% miscarriages, 2.4% abortions, 0.3% stillbirths, 16.9% terminated pregnancies and 2.1% sexually transmitted infections (STI). Sexually abused women (SAW) showed higher likelihoods of non-live births, STIs, miscarriages, abortions and pregnancy terminations. SAW had a 65% higher risk of miscarriages, while those experiencing physical violence had a 64% increased risk of abortions. IPV significantly impacts women's RH in Northeast India. This study presents evidence from surveys on sexual and RH among married women affected by IPV in Northeast India.

Investigation of the atmospheric boundary layer characteristics over a high altitude station in North East India using measurements and reanalysis datasets

Investigation of the atmospheric boundary layer characteristics over a high altitude station in North East India using measurements and reanalysis datasets

Spillover of Newcastle disease virus to Himalayan Griffon vulture: a possible food-based transmission.

The Newcastle disease virus (NDV) affects wild and domesticated bird species, including commercial poultry. Although the diversity of NDV in domestic chickens is well documented, limited information is available about Newcastle disease (ND) outbreaks in other bird species. We report an annotated sequence of NDV/Vulture/Borjuri/01/22, an avirulent strain of NDV reported from Borjuri, Northeast India, in Himalayan Griffon vulture. The complete genome is 15,186 bases long with a fusion protein (F) cleavage site 112GRQGR↓L117. The phylogenetic analysis based on the F protein gene and the whole genome sequence revealed that the isolate from the vulture belongs to genotype II, sharing significant homology with vaccine strain LaSota. The study highlights the possible spillover of the virus from domestic to wild species through the food chain.

Description of Protosticta khasia sp. nov. and Yunnanosticta siangi sp. nov., with new records of P. samtsensis Gurung & Phan, 2023 from Northeast India (Odonata: Zygoptera: Platystictidae)

Protosticta Selys is a genus of damselflies of the family Platystictidae Kennedy found in forests of tropical Southeast Asia. The genus Protosticta has rarely been reported from Northeast India. In this paper, we describe Protosticta khasia sp. nov. (subfamily Protostictinae Dijkstra et al.) based on holotype male and paratype female collected from Maraikaphon, East Khasi Hills district, Meghalaya, India. Protosticta khasia can be identified by the markings of the prothorax and the shape of the male paraproct with two arms. We also describe Yunnanosticta siangi sp. nov. (subfamily Sinostictinae Wilson) from Arunachal Pradesh, India, based on two males and two females. This species is differentiated from its congeners by the thoracic and abdominal markings as well as the shape of male caudal appendages. The key for males of Yunnanosticta is provided. Additionally, we provide new records of Protosticta samtsensis Gurung & Phan, along with an updated key to the Protosticta species of Northeast India.

“Air pollution from biomass burning in India”

Abstract Air Pollution is the most difficult challenge India is facing today and anthropogenic biomass burning (ABB) is one of the major and least understood sources leading to serious health and climate implications by affecting air quality, visibility, atmospheric chemistry, the Earth’s radiation budget, and biogeochemical cycling. Scientific understanding on the composition, chemistry, and regional dynamics of BB emissions is still limited constraining the implementation of appropriate research and policy interventions. The broad categories, associated complex emissions and spatio-temporal variations of ABB in India are discussed here. Major types of ABB prevalent year-round all over India include BB for cooking, heating purpose and open waste burning. Moreover, crop residue burning (CRB) in Indo-Gangetic Plain (IGP) during pre (April-May) and post-monsoon (October-November) seasons; CRB in South-India during January-February; forest fires in Central India and slash & burn agriculture in North-East India during March-May are the other dominant sources active during specific months and regions. Over the IGP, CRB along with other episodic ABB events and stagnant meteorology result in severe air quality and poor visibility (< ~300 m) with reported daily mean PM2.5 concentration shooting upto 15 times higher than Central Pollution Control Board standards. When compared with wheat residue burning, higher fire counts and emissions are reported during paddy residue burning events. During winters, BB contribution to 37% of aerosol oxidative potential in Delhi indicates its health implications. Meta-analysis of data obtained from representative source apportionment studies on PM10 shows >24% BB contribution in Assam, Ahmedabad, Kanpur, and Visakhapatnam; 20-24% in Patiala and Kolkata; 10-14% in Delhi. In PM2.5, BB contribution of >24% in Ahmedabad and Agra; 15-19% in Delhi, Mumbai, and Kolkata is reported while in PM1, BB contributed 19-24% in Kanpur, Patiala, and Assam and <10% in Delhi. Observed spatio-temporal variations in ABB sources and composition over India call for region specific solutions through airshed-based management.

Analytical Study of Deori Ethnic Identity Living in Assam

Like every tribe living in the north-east of India, the Deori community too has its own cultural identity. Deori culture has contributed immensely in giving a diverse and perennial look to the larger Assamese culture. The Deoris, who mainly live in Assam and Arunachal Pradesh, belong to the Assamese-Burmese branch of the Tibeto-Burmese region of the Sino-Tibetan language-family in anthropological considerations and in linguistic terms. Not all Deori people use Deori because of the geographical location of the Deori people living in different parts of Assam and are influenced by different language speakers. There are four faids of the Deori tribe. These are: 1) Dibangia Faid 2) Tendapania Faid 3) Bargaya Faid and 4) Patargaya Faid. Out of these four faids, only among the Dibangiya Fayeds is the present Deori language. The people of these Dibangiya Faids are living in the districts of Lakhimpur, Dhemaji, Jorhat, Tinsukia, etc. in Assam. In formal activities, these people speak Assamese language. In the past, the language was prevalent among all the elders of the Deoris, though the Bargiya and It is not known when the people of Tengapaniya Faid abandoned their language and adopted Assamese as their mother tongue. It is possible that due to contact with the Assamese language, it can be thought that these Faizs stopped speaking their language. Our research article attempts to discuss the Deori tribal history of Assam in a holistic manner. Key word - Deori Caste Introduction, Deori Caste History, Deori Caste, Culture

Morphological characterisation of ethnomedicinally important Kaempferia L. (Zingiberaceae) and its present distribution status in Manipur, North-East India

Kaempferia L., a member of the Zingiberaceae family, is one of the most potent medicinal plants in India and requires proper attention. Our efforts to collect various species of Kaempferia in their natural habitat led to the collection of 30 accessions, including K. galanga, K. marginata, K. parviflora, K. rotunda, and five other unidentified Kaempferia species that are likely natural hybrids with no distinguishing features. It has been found that rhizomes are the most usable portion of the plant, and people in this region use them the most for medical purposes. The present study aimed to describe and evaluate the morphological structures of the plant, incorporating 52 phenotypic descriptors. Descriptive statistics and multivariate analysis were employed to explore diversity. The majority of the traits tested were highly variable. The elevation range (28704.02%) and plant height (at 648.03 %) had the largest coefficients of variation (CV %), whereas anther length (0.06 %) and corolla shape (0.19 %) had the lowest. Rhizome size has a high positive correlation with the odour of the aerial plant parts, growing, dormant, new shoots sprouting, and flowering seasons. However, it shows negative correlations with elevation, lifespan of the flower, and number of leaves. Principal component analysis (PCA), revealed that the first five components accounted for 89.90 % of the variability, and hierarchical grouping based on accession dissimilarity revealed two significant groupings. It was found that wild K. species populations were genetically diverse, suggesting that this diversity can be used for agronomic and horticultural purposes to isolate and characterise numerous important, well-adapted genotypes with the potential to significantly increase yields. Therefore, it is crucial to conserve the genetic material that is currently available.

Optical Properties and Possible Origins of Atmospheric Aerosols over LHAASO in the Eastern Margin of the Tibetan Plateau

The accuracy of cosmic ray observations by the Large High Altitude Air Shower Observatory Wide Field-of-View Cherenkov/Fluorescence Telescope Array (LHAASO-WFCTA) is influenced by variations in aerosols in the atmosphere. The solar photometer (CE318-T) is extensively utilized within the Aerosol Robotic Network as a highly precise and reliable instrument for aerosol measurements. With this CE318-T 23, 254 sets of valid data samples over 394 days from October 2020 to October 2022 at the LHAASO site were obtained. Data analysis revealed that the baseline Aerosol Optical Depth (AOD) and Ångström Exponent (AE) at 440–870 nm (AE440–870nm) of the aerosols were calculated to be 0.03 and 1.07, respectively, suggesting that the LHAASO site is among the most pristine regions on Earth. The seasonality of the mean AOD is in the order of spring > summer > autumn = winter. The monthly average maximum of AOD440nm occurred in April (0.11 ± 0.05) and the minimum was in December (0.03 ± 0.01). The monthly average of AE440–870nm exhibited slight variations. The seasonal characterization of aerosol types indicated that background aerosol predominated in autumn and winter, which is the optimal period for the absolute calibration of the WFCTA. Additionally, the diurnal daytime variations of AOD and AE across the four seasons are presented. Our analysis also indicates that the potential origins of aerosol over the LHAASO in four seasons were different and the atmospheric aerosols with higher AOD probably originate mainly from Northern Myanmar and Northeast India regions. These results are presented for the first time, providing a detailed analysis of aerosol seasonality and origins, which have not been thoroughly documented before in this region, also enriching the valuable materials on aerosol observation in the Hengduan Mountains and Tibetan Plateau.

Living with diabetes in Northeast India: An exploration of psychosocial factors in management

PurposeIndia is the ‘Diabetes Capital of the World’ and accounts for one in seven adults living with diabetes worldwide. Psychosocial, economic, and cultural correlates of disease have important implications for disease management but are rarely explored in India. The purpose of this study is to address psychosocial and cultural factors in diabetes management in the northeastern region of India which has a high disease burden. MethodsThis study attempts to explore the psychosocial and lived experience of diabetes in the northeastern state of Meghalaya. The sample was selected from individuals attending an outpatient facility of a multi-speciality clinic. Semi-structured interviews were conducted with 25 individuals (13 women and 12 men), above the age of 40 years, who had been diagnosed with diabetes for at least 6 months. The narratives were analysed using thematic analysis. ResultsUsing the social cognitive framework, themes were organized in terms of a thematic map linking knowledge of diabetes to the perception of diabetes as ‘a silent killer’, to coping, leading to self-efficacy. However high self-efficacy, over time, may lead to complacency, disrupting health behaviours and requiring re-establishment of those behaviours. Adequate knowledge along with cognitive adaptation and self-efficacy were important constructs that contributed to behaviour change and maintenance. Elements of the cultural context were observed in the spiritual aspects of adaptation, the socially isolating consequences of diabetes, as well as gender differences in social support and management. ConclusionUnderstanding the lived experiences of patients contributes to planning more effective interventions keeping the social and cultural context in mind for more effective management of diabetes. Additionally, acknowledging and supporting women's needs in diabetes management is called for.

Mesozoic tectonics of the Indo-Burmese wedge: a record from the high-pressure metamorphic rocks of the Nagaland-Manipur Ophiolite Belt, NE India

Mesozoic tectonics of the Indo-Burmese wedge: a record from the high-pressure metamorphic rocks of the Nagaland-Manipur Ophiolite Belt, NE India

CLINICAL AND LABORATORY PROFILE OF PATIENTS WITH HEPATITIS B INFECTION ATTENDING THE OUTPATIENT DEPARTMENT OF A TERTIARY CARE HOSPITAL IN NORTHEAST INDIA

Objective: The objective of this study was to analyze the clinical and laboratory profile of patients with hepatitis B infection-attending outpatient departments of tertiary care hospitals in northeast India. Methods: This was a cross-sectional study conducted in the outpatient department of a tertiary care medical institute situated in northeast India. Eighty patients infected with hepatitis B (on the basis of serological markers) were included in this study on the basis of predefined inclusion and exclusion criteria. Demographic details such as age, gender, and socioeconomic status of all the patients were noted. A detailed history was taken including any history of intravenous drug use, tattooing, sexual contacts, history of blood transfusions, and familial liver disease. Clinical and laboratory profiles (liver function test and serological markers) of all the patients were studied. Ultrasound imaging was done in all the cases. p<0.05 was taken as statistically significant. Results: Out of 80 studied cases, there were 49 (61.25%) males and 31 (38.75%) females. The mean age for males and females was 32.30±8.03 and 34.70±13.52 years, respectively. There was no significant difference in mean age between males and females (p=0.3218). Mother-to-child transmission was evenly distributed with 7 males (8.75%) and 9 females (11.25%) affected. Other risk factors, such as dental implants and surgeries, showed a lower prevalence, with dental implants impacting 2 males (2.5%) and 3 females (3.75%) and surgeries concerning 5 males (6.25%) and 3 females (3.75%). Majority of the patients (52.5%) were asymptomatic and were found to be hepatitis B surface antigen (HBsAg) positive incidentally. HBsAg was positive in all cases. 12 (15%) patients showed the presence of hepatitis B e antigen suggestive of high infectivity. Anti-HBc and anti-HBe were positive in 68 (85%) patients each. Hepatomegaly was seen in 23 cases (28.75%) on ultrasound. Moderate fibrosis on elastography was seen in 2 (2.5%) cases. Conclusion: In cases of hepatitis B, the majority of the patients remained asymptomatic, and many cases no risk factor for hepatitis B virus infection could be identified. It is therefore important to screen the general population for hepatitis B infection.

Ecological Flows Assessment of Significant Fish Species in Iril River, Northeast India Through PHABSIM

Background: Freshwater fishes are facing alarming threats due to various anthropogenic activities. The present study estimates the ecological flow requirements for Bangana dero and Wallago attu fish species in the Iril River through a habitat modeling approach. Methods: The habitat suitability modeling of the target species was carried out using the physical habitat simulation model (PHABSIM). PHABSIM model was developed for the river stretch extending about 6,000 m in Iril River. 11 cross-sections at a distance of about 500 m were specified in the model. In the model, habtae was set to run and weighted usable area (WUA) was obtained as output from the habitat model. Result: The highest WUA for the two fish species is estimated at 21 cumecs of discharge. The mean flow of the Iril River is about 27.7 cumecs, which is 6.7 cumecs higher than the optimal ecological flow requirements. The estimation of ecological flow requirements is required to have a better understanding of Weighted Usable Area (WUA) for planning and management strategies. This information may enable stakeholders to develop ameliorative strategies and adopt meaningful measures suitable for the conservation of significant fish species.

Exostoma sentiyonoae, a new catfish (Teleostei: Sisoridae) from Nagaland, Northeastern, India

Exostoma sentiyonoae, a new species of glyptosternine catfish is described from the Dzuleke River, a tributary of the Barak River in Nagaland, northeastern India. This is the fourth species of Exostoma described from the Barak drainage. The new species can be distinguished from congeners by the adipose fin adnate to the upper procurrent caudal-fin rays, presence of tubercles on dorsal-fin spine, anterolateral surfaces of lip with parallel and rounded striae, slender head 7.7–13.1% SL, long dorsal-adipose distance 16.8–24.6% SL, small eye 5.1–8.8 % HL, and 41 vertebrae. Two species groups within the genus Exostoma are proposed; Group I, in which the adipose fin is confluent with the upper procurrent caudal-fin rays, and Group II in which adipose fin is separate from the upper procurrent caudal-fin rays.

Deciphering multi-temporal scale dynamics in the concentration, sources and processes of near surface ozone over different climatic regions of India.

This study aims to investigate the factors influencing seasonal and long-term (2003-2021) changes in the near surface ozone (850 hpa) concentrations over different climatic sub-regions of India. Detailed comparison of daily (2019-2021) near surface ozone values of ERA-5 and CAAQMS (Continuous Ambient Air Quality Monitoring Stations) ground-based measurements revealed that ERA-5 is temporally in phase with CAAQMS measurements falling indifferent climatic sub-regions of India. ERA-5 near surface ozone shows statistically significant long-term (2003-2021) positive trends [2-4 percent per decade (ppd)] over most of the climatic sub-regions, over Indo-Gangetic Planes (IGPs), Southern and Central India trends are particularly strong. Trends were also estimated for each season separately, which were largely positive (2-6 ppd) over Central and Southern India in the Autumn and Winter seasons. Extensive climatological analysis reveals that the reversal of winds in the Indian monsoonal system plays a vital role in such trend patterns across the Indian subcontinent. South-westerly winds from June through September presumably bring ozone deficit air of marine origin, thus causing a dilution effect while the North-easterly winds during late Autumn and early Winters plausibly bring ozone-rich air from the stratospheric-tropospheric efflux dominated Himalayan region. It allows near surface ozone enhancement over Central and Southern India. Seasonal Principal component analysis (PCA) revealed that precursor gases (CH4 and NO2) and climatic variables especially specific humidity (SH) are the primary drivers of near surface ozone variability in the Winter season, while in Spring, climatic variables like boundary layer height (BLH), temperature (T) and SH have a significant role. Principal component regression (PCR) reveals a long-term increase in near surface ozone levels mostly dominated by precursor concentration over IGPs and Southern sub-regions. Whereas, BLH, T and SH significantly explain near surface ozone trends over North-eastern and Coastal India.

To study the survival outcomes of uncommon recurrences among patients with cervical cancer compared with loco-regional and nodal recurrences at a tertiary care center in North East India – Bridging the knowledge gap in the existing literature.

BackgroundRecurrence rates of FIGO stage IB-IIA and IIB-IVA cervical cancer 28–64 respectively. There is a scarcity of data on the recurrence recurrence pattern for unusual sites and theirrecurrence pattern for unusual sites and its association with survival and prognosis. ObjectiveTo study overall survival in patients with distant metastasis compared to local and regional nodal metastasis. MethodsA retrospective study was done from 1/1/2017 to 30/12/22. Cervical cancer patients post primary treatments were included. Survival was analyzed with respect to 3 groups local, regional nodalconducted from 1/1/2017 to 30/12/22. Cervical cancer patients who had received primary post-primary treatments were included. Survival was analyzed with respect to three groups: local, regional nodal, and distant metastasis. Results225 patients had recurrences post-completion of primary treatment, of which 105 (46.6%)(46.6 %) had local, 46 (20.4%)(20.4 %) had regional nodal, and 74 (33.3%) had distant recurrences. The median time for recurrence in local, regional nodal, and atypical recurrences were 9, 9, and 13 months (p value - <0.05), respectively. Treatment included systemic chemotherapy 122 (54.2%), metronomic therapy 19 (8.4%), palliative radiotherapy 44 (19.5%), palliative surgery 8 (3.5%) and best supportive care 30 (13.3%) patients. Median Time to treatment-death of patients after recurrence in local, nodal and distant recurrences was 17.0 months, 18.0 months and 10.0 months respectively (p value - < 0.05). Overall Survival of patients after primary treatment with local, nodal and distant recurrences was 35.0 months, 47.0 months and 50.0 months respectively (p value <0.05). ConclusionLocal recurrence is most common, followed by regional, nodal, and distant recurrences. Overall survival post recurrence was lowest for distant recurrences and highest for local recurrences however overall survival after primary treatment completion was highest for distant recurrence due to the late presen; however, tation of distant recurrences.

Observation and Model Simulation of Aerosol Optical Properties and Size Distribution Over the Hilly Terrain of Northeast India

Observation and Model Simulation of Aerosol Optical Properties and Size Distribution Over the Hilly Terrain of Northeast India

A traditional fermented bamboo shoot reduces intracellular fat accumulation and promotes fat browning in differentiated 3T3‐L1 adipocyte cells through the activation of the AMPK signaling pathway

AbstractFunctional foods, such as fermented bamboo shoots, have a long history of consumption among the ethnic communities in northeast India. These locally fermented bamboo shoots contain a wealth of beneficial microbes and metabolites that can help combat metabolic syndromes like obesity. However, the precise effects and mechanism behind fermented bamboo shoot products and their anti‐obesity properties remain unknown. This study aims to explore the different types of fermented bamboo shoot products to determine their potential anti‐obesity effects as well as to analyze their microbial diversity and metabolite profiles. Using both culture‐dependent and culture‐independent methods, we found a high abundance of lactic acid bacteria from the Firmicutes and Proteobacteria phyla in the sample. Gas chromatography–mass spectrometry (GC–MS) based untargeted metabolite profiling detected several aroma‐active compounds, bioactive metabolites, short‐chain fatty acids, and essential amino acids in the samples. The water extract derived from a particular type of fermented bamboo shoot, Melye‐amiley, was found to significantly reduce intracellular lipid accumulation in cultured 3T3‐L1 cells. In addition, this extract increased the expression of lipolytic (hormone‐sensitive lipase, lipoprotein lipase, and adipose triglyceride lipase) and browning regulator genes (uncoupling protein [UCP1], PRDM16, and PGC1‐alpha). By activating the AMPK signaling pathway, the water extract from Melye‐amiley also upregulated thermogenic protein expression and promoted mitochondrial biogenesis and fatty acid β‐oxidation. These findings suggest that fermented bamboo shoot extract has promising anti‐obesity effects by boosting energy expenditure in white adipocytes. Future research is necessary to identify the active ingredient(s) that may lead to new therapies to treat obesity.

Treatment regimens and survival among patients with head and neck squamous cell carcinoma from Mizo tribal population in northeast India – a single centre, retrospective cohort study

Patients with early-stage head and neck squamous cell carcinoma (HNSCC) are treated using a single-modality approach that involves either surgery (S) or radiotherapy (RT). Conversely, those with advanced-stage disease are treated using a multi-modality approach incorporating a combination of chemotherapy (CT), RT and S. In addition to behavioural factors, such as alcohol and tobacco use, clinical parameters, such as leukocyte and neutrophil counts and T and N classification, have been linked to the survival of patients with head and neck cancer. This retrospective study was designed to provide insights into the types of treatment (induction chemotherapy [IC], concurrent chemoradiotherapy [CCRT], S and RT) administered to patients with HNSCC in Mizoram, analyse their 2-year outcome, and identify potential factors that may affect the response to treatment. A retrospective cohort study was conducted using patients diagnosed with HNSCC between 2017 and 2020 in Mizoram, northeast India. Data on clinical and demographic factors and treatments provided were collected from medical records from the Mizoram State Cancer Institute, Mizoram. Overall survival (OS) and progression free survival (PFS) were determined for each factor using the Kaplan-Meier method and compared using the log-rank test. Cox regression analysis was used to identify the factors that affected OS and PFS. Multicollinearity test was performed between the predictors using a variance inflation factor cut-off point of2. A retrospective study was performed on 210 patients with HNSCC who were followed up for a period of 2 years. The findings revealed that hypopharynx was the most affected site, followed by the nasopharynx, oral cavity, oropharynx, and larynx. Regarding treatment regimens, 85/210 (40.5%) of the patients received IC along with CCRT or RT in a sequential manner. Moreover, 86/210 (41.0%) underwent CCRT alone, 22/210 (10.5%) received RT alone and 17/210 (8.1%) underwent surgery followed by adjuvant CCRT or RT. Two-year OS and PFS estimated using the Kaplan-Meier analysis were 78.1% (95% CI=72.4%-84.2%) and 57.4% (95% CI=50.8%-64.8%), respectively. Log-rank test showed that leucocytosis (p=0.015) and neutrophilia (p=0.014) exerted effects on OS, whereas nodal involvement (p=0.005), neutrophilia (p=0.043) and IC (p=0.010) exerted effects on PFS. Multivariate analysis indicated that leucocytosis (p=0.010 [OS], 0.025 [PFS]), neutrophilia (p=0.029, 0.033), cancer site (laryngeal) (p=0.009, 0.028) and nodal involvement (N2) (p=0.020, 0.001) were predictors of poor OS and PFS. OS was better than PFS in HNSCC patients from Mizo population. Multi-modality approach offered survival advantages over single-modality approach. Leucocytosis, neutrophilia, nodal involvement, and cancer sites were associated with poor OS and PFS. More comprehensive research with a larger sample size is needed to confirm the findings from this study. There is no funding for this study.

Assessing classification system for landslide susceptibility using frequency ratio, analytical hierarchical process and geospatial technology mapping in Aizawl district, NE India

Landslides are a severe geological hazard in northeastern India, particularly in Mizoram’s Aizawl district. To assess this hazard, we conducted a landslide susceptibility mapping study using the frequency ratio (FR) and analytical hierarchy process (AHP) methods. Twelve factors, including slope, elevation, aspect, curvature, topographic wetness index, topographic ruggedness index, rainfall erosivity factor, geology, land use land cover, normalized difference vegetation index (NDVI), and distance to road, were considered. The final susceptibility maps were created by combining these factors, each weighted according to its importance. Since no standard classification guidelines existed, we compared different systems like GIS-based geometric interval (GIC), natural breaks (NBC), and quantile interval (QIC) with mean-standard deviation (MSC). The area was divided into five susceptibility zones: very high, high, moderate, low, and very low. We evaluated the accuracy of these systems using success rate curve (SRC) and quality sum ratio (Qs) techniques. SRC results showed similar performance for GIC, NBC, QIC, and MSC classifications. The AHP method also yielded comparable results. After analyzing the AUC under SRC and Qs, we selected the MSC classification system as the optimal approach for landslide susceptibility mapping. Notably, the distance to roads factor had the highest predictive value, highlighting its importance in identifying slope instability for effective management strategies. As landslides pose significant risks in northeastern India, and our study using FR and AHP methods, along with MSC classification, provides valuable insights for mitigating this geological hazard.