The literature on green supply chain (GSC) typically considers green quality (GQ) as the only quality of a green product. If there exists a trade-off in production of GQ and non-green quality (NGQ) of the product, then both the quality dimensions should be treated as separate decision variables. This paper addresses the GQ and NGQ choices of manufacturers, and price determination by the retailer, in a two-echelon supply chain consisting of a single retailer and many manufacturers, when there exists such a trade-off at GQ level above a threshold. Demand comes from two types of consumers – the ‘traditional’ and the ‘environmentally aware’. A centralized model having the objective of maximizing supply chain profit has been developed and has been compared to a Stackelberg game between the retailer and manufacturers. Cournot-Nash competition, as well as collusion among the manufacturers, have been analysed. This is the first paper to consider manufacturer collusion in a GSC in the presence of trade-off in production of GQ and NGQ. It was found that with only a few manufacturers, GQ is highest in the centralized model, but with a larger number of manufacturers competition among the manufacturers results in higher GQ. Degradation of GQ due to increased cross GQ sensitivity is prevented if manufacturer competition is ensured under Stackelberg game policy. Manufacturer collusion results in degradation of both GQ and NGQ. With an increase in the share of ‘environmentally aware’ consumers, GQ increases and NGQ deteriorates.