Haze returns to Mumbai, pollution in ‘poor’ category

The pollutant-measuring indicator - air quality index (AQI) read 219 (poor) on Saturday.

After two days of moderate air quality, hazy conditions covered the city’s skyline on Saturday.

Haze hangs over Elphinstone in Mumbai on Saturday. (Samson Tupdal)

The pollutant-measuring indicator - air quality index (AQI) read 219 (poor) on Saturday and is expected to be 215 (poor) on Sunday, according to the System of Air Quality Weather Forecasting and Research (SAFAR).

The city had recorded ‘satisfactory’ AQI levels on Wednesday at 98, and thereafter pollution levels began increasing with an AQI of 124 (moderate) on Thursday and 171 (moderate) on Friday.

AQI levels for PM2.5 pollutant (small pollutant particles that can easily enter the lungs and cause ailments) in the range of 0 to 50 is good, 51 to 100 is satisfactory, 101 to 200 is moderate, 201 to 300 is poor, 301 to 400 is very poor, and above 400 is severe.

Researchers said weather conditions were responsible for the poor air quality. “While temperatures are not very low in Mumbai, the high moisture levels are allowing pollutant particles to tread close to the surface. Owing to negligent wind speed and the process of inversion, the particles are not dispersing fast enough, leading to haze formation,” said Gufran Beig, project director, SAFAR. “Until wind speed picks up, the haze is likely to stay.”

Meanwhile, the day temperature, both in Santacruz and Colaba were above the 30 degree celsius-mark on Saturday -- closer to normal levels first time since cyclone Ockhi stormed by the city in the first week of December. Minimum temperatures also increased but were a degree celsius below normal. Moisture levels were high as 95% humidity was recorded during the day that dropped to 84% by Saturday evening.