The Economic Times , Monday, January 11, 2016

Correspondent : AnubhutiVishnoi

NEW DELHI: With five more days to go before the odd¬even experiment in Delhi draws to a close, the jury is still divided on how much impact the much¬debated vehicle rationing system has had on the capital's air. The lack of clarity is compounded due to the weather playing truant. Most agencies keenly monitoring Delhi's air quality during this period are unable to firmly conclude yet whether the odd¬even plan is helping to bring down the pollution levels. Higher wind speed and mild showers have also played their part in improving the air quality. Factor in the data generated by National Air Quality Index¬AnandVihar, which throws up the most shocking air pollution data in the capital every day, air quality has been in the range of 'severe' before and right through the odd¬even plan's duration until Saturday when weather changes brought down the pollution levels by a near 100 points and air quality moved to a 'very poor' range. SAFAR's data from across 8 stations that it monitors also showed Delhi's overall air quality improving from the 'severe' range to the 'poor¬moderate' range when cool breeze swept the capital on Saturday with mild showers also washing down the pollutant overload. Dr GufranBeig, scientist with SAFAR (System of Air Quality and Weather Forecasting & Research) of Indian Institute of Tropical Meteorology which is closely tracking Delhi air since January 1, told ET that the weather was playing a 'decisive role'. "We cannot conclusively say anything yet as the weather is playing a decisive role. Until two days back, weather was playing rather spoilsport with air stagnation and moisture levels high. After some thundershowers on Saturday, all pollutant levels in the capital have declined very sharply by a good 100 points. So in this period we have had two contrasting spells of weather which has become the strongest factor.Generally speaking, yes there is some impact but we can only say in another week or so when similar weather conditions prevail," Beig told ET. Anurabha Ghosh, CEO of Council on Energy, Environment & Water, also agreed that there is no firm assessment yet of the odd¬even impact but conceded that so far data did not show any significant difference. "This is just a week's data and so far not much change can be seen in air quality or even in traffic. In some locations, air pollution/quality has remained stable and in some others the pollution levels can be seen as marginally less. We will look at the data this week and historical data from last year as well and also factor in weather conditions before a final assessment. It is clear though that it has worked well as a social experiment so far. Hard data though will need few more days and mapping with similar weather conditions," Ghosh told ET. The Centre for Science & Environment, on the other hand has argued that the scheme has resulted in the "lowest pollution peak compared to the previous high smog episodes this winter" and that despite the lower wind speed observed on some days in scheme's duration, pollution levels dipped.

SOURCE : http://economictimes.indiatimes.com/news/politics-and-nation/experts-still-divided-on-odd-even-schemes-impact-on-delhis-air-quality/articleshow/50524745.cms?prtpage=1