The odd-even experiment in the national capital yielded little in terms of reducing air pollution or congestion on the city roads, initial findings of an IIT-Delhi study has found.
In fact, the preliminary report says that average speed of vehicles “decreased” by a small amount between 8 AM and 11 AM when the restrictions were in force across locations.
The licence-plate policy, which is set to make a comeback on April 15 in Delhi, managed to reduce car use by about 35 per cent and not “50 per cent”, the report prepared by Transportation Research and Injury Prevention Programme of IIT-Delhi observes.
It says the benefits of the programme on the day-time air quality were not immediately apparent in the ambient measurements, due to meteorological factors and suggests that at least 20 monitoring stations are required for a “reliable analysis” of its effectiveness.
The Delhi Pollution Control Committee (DPCC) now has six such stations. The government, in its recent budget, has allocated money to build three more stations that monitor real-time air quality.
More importantly, it suggests that the decrease in emissions from cars may be “offset” by an increase in flow of other vehicles such as buses, three-wheelers and motorised two-wheelers.
“In the lightof the fact that increase in flow of buses, three wheelers and motorised two-wheelers seems to be of a similar magnitude as the decrease in car flow, the effect of decrease in PM 2.5 emissions by cars would be even less,” it notes.