IT’S NOT just Diwali crackers that has led to the thick cover of smog over the city, bringing down visibility to 2,000 metres during the early morning and evening hours since Saturday. The meteorological department (MET) cited stubble burning along with firecrackers as the main reasons for the fall in the visibility. On a normal day, the visibility in the city is 5-6 kilometres.
“The smog cover is largely due to stubble burning, bursting of crackers in the past few days and a dip in temperature,” said Surinder Paul, director, meteorological centre, Chandigarh, adding that the condition would continue for the next few days.
The dry condition and fall in night temperature created the right conditions for the smog cover, Paul said. If it had been warmer, the heat convection rising from the ground would have pushed the suspended particles up into the atmosphere, but cold air tends to push the particles down. The minimum temperature in the city on Monday evening was 14.4 degrees Celsius while the maximum temperature was 30 degrees Celsius. “The drop in temperature is an indication that this year the winter will be colder than last year,” added Paul.
Last year, winter season was shorter and warmer. The minimum temperature remained 4 to 5 degrees high through the winter season. Overall, 2015 was the warmest on record as annual average minimum temperature of Chandigarh was the highest since its record. El Nino was one of the major factors for it. El Nino, which refers to a climate cycle in the Pacific Ocean with a global impact on weather patterns, was the strongest in recent years. There were other factors such as a change in pattern of Western Disturbance for warmer winters.