Congress President Sonia Gandhi commented on the putrid quality of Delhi air. She was speaking at an event to felicitate the Centre for Science and Environment. The NGO won the Indira Gandhi Award for Peace, Disarmament and Development. In her speech, Sonia called Delhi notorious for being one of the most polluted cities in the world. She also remembered how the air quality in the national capital had changed after CNG-propelled public transport was introduced.