India, Oct. 31 -- Five years is long enough to judge whether a new idea is taking root. When the Swachh Vayu Sarvekshan was introduced in 2022-23 under the National Clean Air Programme (NCAP), its purpose was simple: encourage cities to move beyond drawing up clean-air plans and start implementing them. The annual assessment offered a way to recognise cities tackling major sources of pollution, while fostering competition among urban local bodies. Five years on, the initiative has evolved considerably.

The 2026 survey ranked Lucknow first among cities with populations of more than 1 million, followed by Indore, Jabalpur, Bhopal and Agra. But the leaderboard tells only part of the story. More revealing is the journey behind the rankings....