The city woke up to a cool Tuesday morning as the minimum temperature recorded at 5.30am fell 5.2 degrees Celsius below normal, making it the lowest November night temperature since 2013.
The night temperature recorded at the Santacruz weather station, representative of Mumbai, was 16.7 degrees Celsius, while the temperature recorded at the Colaba weather station was 22.7 degrees Celsius, which is almost a degree Celsius below normal.
Owing to the drop in temperatures, the city recorded a spike in pollution levels. The air quality index (AQI) levels, the pollutant-measuring indicator, shot up to 236 (poor category) on Tuesday as compared to 216 recorded on Monday, observed researchers from the System of Air Quality Weather Forecasting and Research (SAFAR). An AQI of 233 (poor) has been predicted for Wednesday.
AQI levels between 201-300 falls under the ‘poor’ category and 301-400 is ‘very poor’, indicating a health risk for people sensitive to air pollution.
“The drop in temperatures combined with low wind speed and less moisture increases pollution levels,” said Neha S Parkhi, senior programme officer, SAFAR. “Pollution is likely to remain in the ‘poor’ category unless one of these weather factors change.”
Meanwhile, in 2012, Mumbai recorded its second lowest November night temperature in the last decade at 14.6 degrees Celsius. However, the lowest for the decade was recorded in 2007 at 14.4 degrees Celsius. The all-time low November minimum was recorded at 13.3 degrees Celsius in 1950.
Weather bureau officials said low temperatures are likely to continue owing to shift in wind direction over the city. “As winter approaches, the wind pattern is shifting from north-easterly to northerly, which means winds are carrying cold air from the north. We expect a further drop in temperatures if there is a complete shift to northerly winds,” said an official from the Regional Meteorological Centre in Mumbai.
The city also recorded a significant drop in moisture levels as Colaba and Santacruz recorded 25% and 75% humidity on Tuesday morning.
The most polluted locations in the city on Tuesday were Navi Mumbai that recorded an AQI of 303 (very poor), followed by Malad at 302 (very poor) and Bandra-Kurla Complex (BKC) at 300 (poor). However, levels were much lower as compared to Delhi that recorded 460 (severe) for the tenth day in a row.