According to World Health Organisation (WHO)’s urban air quality database, Delhi was rated as the most polluted city in the world in terms of PM (particulate matter) 2.5 levels. But WHO's latest report indicates that Delhi has made a considerable improvement in tackling air pollution and it is no more the most polluted city in the world. The national capital now ranks 11th among 3,000 cities in 103 countries in terms of PM 2.5 and 25th in terms of PM 10 levels. So, the Delhi civic authorities and the state and central governments deserve thanks for the positive action they have taken.