Moisture in air leads to smog

Everyone, including the weather bureau officials, were taken by surprise as a thick layer of high-density smog engulfed the city on Wednesday evening making it difficult for drivers to manoeuvre vehicles.

“Since the temperature is on the higher side, there is no question of fog formation. It might be smog resulting due to pollution and humidity,” said K Sathidevi, deputy director of Regional Meteorological Centre, Mumbai.

The smog started engulfing the city from early evening. Many drivers complained of irritation in the eyes. According to Dr AB Mazumdar, deputy director general of meteorology (weather forecast), Pune, this is a general phenomenon during winter.

“Since the atmosphere is more or less stable during winter, such phenomenon takes place. Its frequency is more during early morning and evening,” he said, adding, when smog formation takes place in the evening, it may persist throughout the night. Generally low wind velocity during winter is the basic reason for smog formation. “High levels of moisture and emissions in atmosphere clubbed with low wind velocity add to persistence of smog. It gets dispersed as the wind velocity increases,” Dr Mazumdar said.