A week into its bold experiment to limit cars on the roads, Delhi has thrown its weight behind the "odd-even" policy but it’s already itching to see it work. Car-owners have rediscovered the joys of zipping through relatively empty roads thanks to a substantial number of private cars being off the roads, even as public transport systems such as the buses and the metro are running on full capacity.

The odd-even policy, even with all its two dozen exemptions, it seems, has been successful in solving the seemingly impossible problem of traffic congestion in the national capital. But what about pollution? The results are nowhere near as sweeping so far. And experts say that there’s a good reason why.

No magic wand

On Tuesday, the average concentration of the major pollutant matter – PM2.5 – was 278.4 micrograms per cubic meter in the capital’s air. By evening, concentration of PM2.5 levels near the Delhi airport had reached 428 micrograms per cubic meter, qualified under the severe category which affects even healthy citizens and could cause long term illnesses while PM10 was recorded at a “very high” level of 355 micrograms per cubic meter of air.

Many expected that taking a substantial number of cars off the road would significantly improve air quality in the city, at least in the short term but that hasn’t happened so far.

There were some positive signs from the pollution readings on the first day of odd-even implementation as emissions came down, and so did the PM2.5 and PM10 levels by approximately 15%, according to the Indian Express. These levels, however, quickly rose by evening, raising fears that it was perhaps too early to call the policy a success on the pollution front.

Experts suggest that even a 15-day trial is too short a period to judge the efficacy of a measure in combating severe air pollution which is a result of toxic emissions over decades.

“At this point, it’s a bit premature to arrive at conclusions about the effectiveness of odd-even policy,” said Shirin Bithal, Research Associate at the Centre for Science and Environment. “The policy came in as an emergency measure because the pollution levels in the capital were dangerously high and it’s not going to work like a magic wand over our pollution problems.”

Bithal argues that vehicles taken together contribute only about one-quarter of pollutants like PM2.5 in Delhi’s air and hence, expecting the policy to reduce their concentration in the air within a matter of days will be expecting too much.

Need for long-term measures

“There are lots of exemptions, two wheelers have been left out as well, which run on petrol and contribute to the air pollution,” she said. “We need to evaluate the policy in the light of other measures as well as take into account the impact of unstable weather in the capital which is oscillating between unusually warm on some days to foggy on others, which further interferes with the readings.”

The Energy and Resources Institute also analysed pollution data over the last week and concluded that levels of PM2.5 in Delhi’s air had indeed risen and shot further away from the prescribed safe limits but noted that it was largely due to atmospheric conditions.

The 24-hourly averaged concentrations at four locations, Mandir Marg, RK Puram, Punjabi Bagh and Anand Vihar, were found to be 5, 5.4, and 1.1 times higher than the safe standards respectively, TERI said. "Analysing the trends between December 24 to January 3, PM2.5 concentrations have increased by 72-176% cent at the four stations. However, this is mainly due to reduced wind speeds during the period," it noted.

Studies analysing pollution in northern India have also pointed out air pollution is a regional phenomenon rather than local and that similar measures need to be carried out in other cities as well to really curb Delhi’s noxious air.

The recent study carried out by Indian Institute of Technology, Kanpur on Delhi’s pollution and its causes also said that measures like odd-even must also be implemented in neighbouring states like Haryana, Punjab and Uttar Pradesh. It also added that winters in Delhi are more poisonous than summers and that causes of air pollution differ in different seasons. For instance, vehicles are the major polluters in winters but in summers it is the burning of coal and fly ash that contributes the most to pollution.

Thus, the study concluded, that air pollution control measures need to be implemented region-wise and in sync with each other. It suggested reducing coal emissions, providing LPG cylinders to all households, vacuuming of roads to tackle road dust and reducing sulphur content in industrial fuel, among other things. Even then, it concluded, that the pollution levels are still likely to be twice as high as the acceptable standards.

Bithal from CSE agreed and said long term measures must be implemented in quick succession to see progress on the pollution front.

“We need to disincentivise car-owners from buying cars by making them more expensive, raising road taxes and reducing parking availability to curb emissions in the long-run,” she said. “The government needs to bring in cleaner fuel emission norms on priority and also make public transport stronger so that those who have switched to it during the odd-even trial continue to leave their vehicles at home.”