Why the odd-even scheme doesn’t make much sense to fight Delhi pollution

Nilanjan Ghosh
Nilanjan GhoshSep 18, 2019 | 12:27

Why the odd-even scheme doesn’t make much sense to fight Delhi pollution

Last week, Delhi chief minister Arvind Kejriwal proclaimed the return of the odd-even rule for traffic movements in the capital after Diwali from November 4 to November 15, 2019. The rule entails that vehicles with odd and even number licence plates will be allowed to ply on alternate days. It seems that Kejriwal’s commitment to combat vehicular pollution is unabated. This is despite certain political corners who feel that the newly furbished ring roads and central schemes are sufficient to fight pollution.


Numbers don’t lie

Indeed, the cost of air pollution is huge for the city. While a 2016 World Bank study revealed that India lost more than 8.5 per cent of its GDP in 2013 due to the cost imposed by labour-day losses and increased social costs, an IIT Bombay study found that the cost imposed by air pollution in Mumbai and Delhi is to the tune of 0.71 per cent of India’s GDP.

This becomes more marked from a recent occasional paper published by ORF, which develops a comprehensive Sustainable Development Goals (SDG) index, also claimed to be an indicator for ease-of-doing-business. Though Delhi ranks third among 23 states in terms of SDG achievements, its rank in SDG 13 (climate action) is 22. In other words, had its score been any better in terms of air pollution, which has 39 per cent weight in SDG 13 index and 3 per cent weight in our overall SDG index, its ease-of-doing-business would have been even better.


Interestingly, a week before the announcement of the odd-even rule, the CM stated that the city’s pollution has declined by 25 per cent over the last three years. Therefore, the question that arises is what prompts such an action when both PM2.5 (particulate matter equal to or less than 2.5 micrometers diameter) and PM10 (particulate matter equal to or less than 10 micrometers diameter) are declining?


The claim seems to be based on the data from the Delhi pollution control committee, which has been monitoring real-time air quality since 2010. While there were initially four stations, the number was increased to 26 in 2018.

Viewed from this perspective, the average monthly emission of PM2.5 has declined from 160 in CY 2012 to 130 in CY 2017 (in 2015 and 2016, they were 133 and 136 respectively), and further to 128 in CY 2018. During the same period, PM10 has declined from 351 in CY 2012 to 277 in both 2017 and 2018 (with figures of 295 and 300 in 2015 and 2016). In 2019, for the months from January to August, the averages for PM2.5 and 10 are 93 and 217 respectively.

Herein lies the ‘catch’. First, the average figures are comparable only between 2012 and 2017, as from 2018 onwards, 22 more better or worse performing stations have been added. This has changed the basis of comparison.

Don’t just blame cars

Second, the data for 2019 misses on the peaking months of November and December, when pollutant levels substantially increase. Therefore, it cannot be concluded that pollution levels have ameliorated in the capital. It also needs to be noted that the levels attained till now are still far above the WHO’s safe air quality benchmarks of 20 ìg/m3 (annual mean) for PM10 and 10 ìg/m3 (annual mean) for PM2.5.


Last year, the Ministry of Earth Sciences attributed almost 41 per cent of PM2.5 air pollution in Delhi to vehicular emissions, 21.5 per cent to dust and 18 per cent to industries. As such, the contribution of transport sector as a source of pollution has increased from 22 per cent in the early 1970s, to more than 70 per cent by the beginning of the 2000s. On the other hand, while Delhi’s air quality index is generally classified as Moderate (101-200) between January and September, it entails a major negative shift to Very Poor (301-400), to Hazardous (500+) levels during October to December. The reasons for these are compounded impacts of firecrackers during festival seasons, the stubble burnings in the agricultural fields in neighbouring states, and, of course, the chilliness in the air, along with the usual sources of pollution.

A short-term panacea

In this way, the ‘odd-even’ rule in Delhi during November is axiomatically justified as an emergency response to temporarily address the problem. When imposed for the first time in January 2016, congestion declined, the average speed of plying in Delhi increased, and consumer choice shifted to public transports. Impact assessment studies, however, reveal variable results.

A study conducted by The University of Chicago, finds that the scheme of January 2016 helped in the reduction of particulate concentrations by 14-16 per cent, while another study by IIT and IIM finds impacts of 2-3 per cent decline in overall pollution levels.

In an Economic and Political Weekly paper published on September 7, IIM Lucknow researchers point out the biggest lacuna. They demonstrate that while the scheme was introduced for private vehicles and two-wheelers, the sensitivity of pollution levels are far higher for commercial vehicles.

This indicates that restrictions on commercial vehicles will have more of an impact on pollution than private vehicles and two-wheelers do. Therefore, the ‘odd-even’ rule will not solve the problem entirely. It can only touch the tip of the iceberg. This rule needs to be viewed as a policy-driven demand-management phenomenon with temporary applications, and needs to be complemented by various other measures to address the problem holistically.

(Courtesy of Mail Today)

Last updated: September 18, 2019 | 13:05
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