As curtains came down on the 'odd-even' pilot scheme, an independent think tank on Friday said there is no "conclusive" evidence to prove that the policy improved Delhi's air quality or reduced traffic congestion.
Council on Energy, Environment and Water (CEEW) which measured air quality and traffic volumes at five important locations in the city said while air pollution levels "increased" in the first week of January, and in the second week despite being marginally better air quality it still remained poor.
The CEEW works in collaboration with the Energy Policy Institute at the University of Chicago (EPIC).
"There is no conclusive evidence to prove that the odd-even policy improved Delhi's air quality or reduced traffic congestion. On the basis of data collected from low-cost air pollution monitors, indicates that the average air pollution levels increased in the first week of January as compared to the previous week.
"However, in the second week of January, air quality was marginally better, but still poorer than the last week of December. The measurements from the low-cost monitors are almost identical to those of the pollution monitors installed by the Delhi Pollution Control Committee," it said.
Delhi Chief Minister Arvind Kejriwal had appealed to the people of Delhi to continue observing the car rationing measures "voluntarily", which the government claimed has reduced air pollution by up to 25 per cent.
It further said average PM 2.5 level of 306 g/m3 was observed during the first two weeks of January 2016, similar to average PM 2.5 level of 330 g/m3 observed during the first fortnight of January 2014.
However, the first two weeks of 2015 had a lower average PM 2.5 level of 226 g/m3 due to unseasonal rains and winds.
"In the short-term, meteorological variables such as temperature, wind speed and precipitation have a significant impact and as a result it is hard to provide conclusive evidence on the impact of the odd-even policy on air quality," it said.
The think tank measured air quality and traffic volumes at five important locations - Connaught Place, GTB Nagar, IIT Delhi, Mathura Road, and Shadipur over the last three weeks.