Breath of fresh air: City no longer among 150 most polluted cities

Navi Mumbai ranks 51; experts say too early to comment on long-term quality trend

MUMBAI: The city has dropped out of an infamous list of the world’s 150 worst polluted cities, revealed an international report released on Tuesday. Based on 2019 data, Navi Mumbai was ranked 51st, while Ghaziabad in Uttar Pradesh was the most polluted city in the world. Fourteen of the world’s 20 worst-polluted cities were in India.

According to Uk-based Iqair’s 2019 World Air Quality Report, Mumbai’s air quality improved in 2019, with the annual average particulate pollution (PM2.5) concentration decreasing by 20% over the past two years.

The report defined PM2.5 as ambient airborne particles that measure up to 2.5 microns in size, which enter the bloodstream via the respiratory system and travel throughout the body, causing far-reaching health effects.

The report ranked Mumbai at 169 in 2019, with an annual average PM2.5 concentration at 43.5 micrograms per cubic metre (µg/m³). In 2018, the city was the 71st most polluted globally at 58.6 µg/m³ and 113th most polluted in 2017 at 54.2 µg/m³.

The most polluted city in Maharashtra — Navi Mumbai — recorded its annual average PM2.5 concentration at 61.6 µg/ m³. Navi Mumbai was the 27th most polluted in India, while Mumbai was the 54th most polluted

among the 90 cities studied.

“While Mumbai’s air quality has improved in 2019, it is still too early to draw a conclusion on the long-term trend. The air quality remains several times above the World Health Organisation (WHO) recommendation of 10 µg/m³, and a lot more efforts must be done to offer clean air to citizens,” said Yann Boquillod, air-quality monitoring director at IQAIR.

Among six Indian capital cities analysed in the report, Mumbai was the third-most polluted after Delhi and Kolkata, with 28.8% of all 2019 days recording ‘unhealthy’ air quality, 19.1% recording ‘unhealthy for sensitive groups’, 43.5% as ‘moderate’ air days, and 1.6% as ‘very unhealthy’. In 2019, January was the most polluted month for Mumbai at 104.5 µg/m³, followed by December at 81 µg/m³, 71 µg/m³ in February, and 59 µg/m³ in March.

While 26 India cities were among the 50 most polluted cities in the world, none were from Maharashtra. Every city in India witnessed a decline in PM2.5 levels from 2018 to 2019, except for Nagpur and Aurangabad.

“Using a weighted average for available data, India’s national air pollution decreased by a remarkable 20% from 2018 to 2019,” said Boquillod.