Green Marketing, Consumer Sustainability Premium and Greenwashing Detection

population) and growing at 22% annually by purchase behaviour metrics according to Nielsen India's 2023 Sustainability Survey, represents a market opportunity and a credibility challenge simultaneously — the same consumers who are most willing to pay sustainability premiums are also the most sophisticated in identifying greenwashing, creating severe reputational risk for brands that make environmental claims unsupported by substantive practice. India's consumer goods, FMCG, and retail landscape is responding with a proliferation of eco-labels, sustainability certifications, and green product ranges — many of which have questionable environmental substance behind the marketing claims. This study examines willingness-to-pay (WTP) for green product premiums across six product categories and three geographic segments (metro, tier-2 cities, rural) based on a conjoint analysis survey of 2,480 respondents; analyses the attitude-behaviour gap in green consumption across four generational cohorts using structural equation modelling; develops and validates a Greenwashing Detection Index based on 28 environmental claim authenticity indicators applied to 156 Indian brand green marketing campaigns; and evaluates eco-label effectiveness (consumer awareness, trust, and purchase lift) across six Indian eco-label schemes. WTP for green premiums ranges from 8% (organic food, rural) to 36.2% (green building, metro), with Gen Z showing the highest attitude-behaviour consistency. Greenwashing is detected in 42% of analysed campaigns using the Greenwashing Detection Index. BEE Star Rating (82% awareness) and FSSAI Organic (74% awareness) are the two most recognisable eco-labels, but both underperform their awareness in purchase lift conversion (24% and 18% respectively).