Bhopal is the capital of the Indian state of Madhya Pradesh and the administrative headquarters of Bhopal district and Bhopal division. The city was the capital of the former Bhopal State. Bhopal is known as the City of Lakes for its various natural as well as artificial lakes and is also one of the greenest cities in India. It is the 17th largest city in the country and 131st in the world. A Y-class city, Bhopal houses various institutions and installations of national importance, including ISRO's Master Control Facility and BHEL. Bhopal is home to the largest number of Institutes of National Importance in India, namely IISER, MANIT, SPA, AIIMS and NLIU. The city attracted international attention in December 1984 after the Bhopal disaster, when a Union Carbide India Limited (UCIL) pesticide manufacturing plant (now owned by Dow Chemical Company) leaked a mixture of deadly gases composed mainly of methyl isocyanate, leading to one of the worst industrial disasters in the world's history. The Bhopal disaster continues to be a part of the socio-political debate and a logistical challenge for the people of Bhopal. Bhopal has been selected as one of the first twenty Indian cities to be developed as a smart city under PM Narendra Modi's flagship Smart Cities Mission and will be the first smart city of India in coming years. The city has been adjudged as the 21st cleanest city in India.