Introduction: Whilst many less developed countries are struggling to provide universal access to safe sanitation, in the last five years India has almost reached its target of eliminating open defaecation. The object of this study was to understand how the Indian Government effected this sanitation transformation. Methods: The study employed interviews with 17 actors in the Governments Clean India programme across the national capital and four states which were analysed using a theory of change grounded in Behaviour Centred Design. Results: The Swachh Bharat Mission (Gramin) claims to have improved the coverage of toilets in rural India from 39% to over 95% of households between 2014 and mid 2019. From interviews with relevant actors we constructed a theory of change for the programme in which high-level political support and disruptive leadership changed environments in districts, which led to psychological changes in district officials, which, in turn, led to changed behaviour concerning sanitation programming. The Prime Ministers setting of the ambitious goal to eliminate open defecation by the 150th birthday of Mahatma Gandhi (October 2019) galvanised government bureaucracy, while early success in 100 flagship districts reduced the scepticism of government employees, a cadre of 500 young professionals placed in districts imparted new ideas and energy, social and mass media was used to engage and motivate the public and key players, and new norms of ethical behaviour were demonstrated by leaders. As a result, district officials engaged emotionally with the programme and felt pride at their achievements in ridding villages of open defecation. Conclusions: Though many challenges remain, Governments seeking to achieve the Sustainable Development Goal of universal access to safe sanitation can emulate the success of Indias Swachh Bharat Mission.