This article provides an important international empirical application of the multiple-streams framework with some theoretical additions that make a novel contribution to the existing scholarship in this field. Using a modified multiple-streams approach (MSA) that extends Kingdon’s original agenda setting model to the decision-making stage, we analyse and explain an empirical puzzle in the context of the environmental regulation of coal-fired power plants, considered central to India’s economic development. The puzzle involves both the content – a stringency comparable to those in more developed economies – and the timing – within a year of a new national government coming to power with the promise of reviving economic growth. Our findings show how a top bureaucrat exploited the agenda window opening in the problem stream to couple the three streams, resulting in the notification of draft environmental standards. The political entrepreneurship of the same bureaucrat led to the adoption of final standards in the same form as the draft in the decision window created by developments during the period leading to the Paris climate summit. The operationalisation of the modified MSA to our empirical case generated new theoretical insights. First, we expand on the original formulation of decision stage dynamics and argue that the decision window could also open due to independent activity in any of the three streams. Second, we argue that transnational politics could act as an additional factor in the ripening of the political stream at the decision stage.