Climate change is a collective action problem that individual firms cannot solve alone, yet the most natural corporate responses, such as jointly phasing out polluting inputs or adopting common sustainability standards, resemble the output restrictions and horizontal agreements that competition law forbids. This paper examines that tension, which it calls the ‘green paradox’: the risk that rigorous cartel enforcement suppresses the private climate action that public policy seeks to encourage. It reviews the responses of the European Commission, the Dutch Authority for Consumers and Markets and the UK Competition and Markets Authority, focusing on ‘out-of-market’ benefits and their quantification, and contrasts them with the United States, Germany, Austria, Japan and Australia. It then turns to India, whose Competition Act 2002 has no dedicated sustainability framework but contains textual hooks, namely the joint-venture proviso to section 3(3), the efficiency factors in section 19(3) and the exemption power in section 54, which a purposive reading could activate. The paper argues that accommodation of green agreements remains incomplete in every jurisdiction examined, and proposes a graduated framework of official valuation benchmarks, rebuttable presumptions and time-limited exemptions, adapted to Indian institutions.