Reliance Infrastructure Limited, formerly Reliance Energy Limited and Bombay Suburban Electric Supply, is an Indian private sector enterprise involved in power generation, infrastructure, construction and defence. It is part of the Reliance Group. The company is headed by its chairman, Anil Ambani, and chief executive officer, Punit Narendra Garg. The corporate headquarters is in Navi Mumbai. Reliance Infrastructure's interests are in the fields of power plants, metro rail, airports, bridges, toll roads, and defence. It is a major shareholder in the other group company, Reliance Power and Reliance Naval and Engineering Limited. In Fortune India 500 list of 2019, Reliance Infrastructure was ranked as the 51st largest corporation in India with first rank in 'Infrastructure Development' category. As of March 2018, Reliance Infrastructure has 56 subsidiaries, 8 associate companies, and 2 joint-ventures. Wikipedia