The alarming rise in pollution over the capital have increased the duration of fog by almost eight hours per day in last 15 years and it promises to be no better this year.
NEW DELHI: Expect winters in the national capital to be more chilly and foggy this year.
The alarming rise in pollution over the capital have increased the duration of fog by almost eight hours per day in last 15 years and it promises to be no better this year.
The longer duration of fog cover, in the city, has also brought down the maximum temperature by 2 to 3 degrees, a study by the Indian Meteorological Department has found
The change in the city's temperature during the peak winter months were due to rise in pollution and long foggy hours, the study said.
The long fog hours also deteriorates the visibility which affects the movement of flights and trains.
"We found that there is a serious deterioration in urban visibility over the capital in last few years and city has hardly experienced good visibility (> 5000)," IMD Director Rajendra Kumar Jenamani, who carried the study told.
The study also found that despite the use of CNG as an automotive fuel in the capital, there was no discernible impact on the pollutants level.
"The annual averages of different pollutants like Nitrogen Dioxide (NO2) and other suspended particulate matter (SPM) in the capital have shown an increasing trend even after the public transport were converted to CNG," he said.
IMD studied the hourly fog data and daily maximum and minimum temperature for December and January in the capital from 1989 to 2003.
"In last three years the day temperature during January had remained below 15 degrees Celsius for many days against the longer period average of 21 degrees," Jenamani said.
There is also a significant increase in the areas of low visibility ranges contrast to alarming fall in high visibility hours at the IGI Airport.
The good visibility (> 5000 m) was 16.97 hours per day in the 1960, but has dramatically decreased to 0.31 hrs in 2005.
The poor visibility ranges with dense fog hours of visibility (< 200 m), there is an increase from 0.20 to 4.17 hours.
"The poor visibility conditions around the airport in the capital have led to cancellations and diversions of flights and delays in train thus severely affecting normal life in winter," Jenamani said.
The study found that rise in NO2 level over the capital was the important factor for increased fog hours. And, the 50 per cent of NO2 emission in air comes from vehicular activity.
"The number of vehicles in the city has just doubled to 4.88 million in last 10 years. Higher emissions from increasing vehicle use in capital, particularly diesel vehicles have contributed to increasing trends for NO2 and SPM," he said.
The emission trends and air quality analysis in the capital reveal that NO2 emissions has been steadily increasing, and SPM levels in air still violate the permissible limit.
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