Mumbai has recorded its hottest October day in eight years, with Santacruz reaching 37.6°C on Thursday, prompting the India Meteorological Department (IMD) to declare a heatwave in Mumbai, Raigad and Ratnagiri for Friday. The warning comes as stagnant air pushes the city’s air quality into the moderate category.
Santacruz’s maximum temperature was the highest recorded there in October since October 28, 2018, when the mercury reached 38°C. Colaba recorded 36.5°C on Thursday, 3.9°C above normal, according to IMD data. Temperatures have remained above normal through the first week of October, with Colaba reaching 37.4°C on October 2, its highest October reading in 13 years, and Santacruz recording the same temperature on October 3, its highest October reading since 2019.
The IMD has also placed Thane and Palghar under a yellow warning for hot and humid conditions. In coastal districts such as Mumbai, a heatwave warning is issued when maximum temperatures remain 4.5°C to 6.4°C above normal for a sustained period.
The weather department attributed the unusual heat to an anticyclonic circulation that has delayed the arrival of the sea breeze. The daily sea breeze normally helps moderate temperatures across Mumbai. “The prevalent anticyclonic circulation has delayed the influx of sea breeze, which plays a crucial role in cooling down the region. This has resulted in a spike in the temperatures,” Sushma Nair, a scientist at the IMD, told The Indian Express.
The lack of wind has also affected the city’s air quality by allowing pollutants to remain suspended for longer. Mumbai’s overall air quality index rose to 120 on Thursday from 91 on Wednesday, moving from the satisfactory to the moderate category under Central Pollution Control Board standards. The CPCB classifies AQI readings from 101 to 200 as moderate.
Fourteen of the city’s 20 active monitoring stations recorded AQI levels above 100. Worli recorded the highest reading at 163, followed by Deonar at 154, Colaba at 151 and Bandra Kurla Complex at 130. “There is no wind, which has left the pollutants suspended in the atmosphere for a prolonged period. Until strong winds flow, the pollutants will not be dispersed,” an official said.
The IMD’s heatwave declaration covers Friday, while the warning for Thane and Palghar identifies continued hot and humid conditions in the two neighbouring districts. The department’s assessment links any improvement in temperatures and air quality to the return of stronger winds and the sea breeze.
