Delhi’s vibrant colours pale as the city gasps for air each winter. Pollution levels soar, with the AQI often exceeding 500. In 2015, the Delhi High Court dubbed the city a ‘gas chamber’ due to its escalating pollution, demanding urgent action from both State and Central governments. With the air quality dipping each year, Delhi implements various measures to combat this crisis. One is the odd-even rule, which the government tried for a few years with limited success.
This year, in response to rising pollution levels, the Graded Response Action Plan (GRAP) was enforced, introducing specific rules based on pollution severity. With each new restriction, one question lingers in the minds of Delhiites: Will the government reintroduce the odd-even rule?
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Some people vouch for the benefits of this rule. However, many experts and citizens are sceptical about its effectiveness as it doesn’t address the underlying issues causing air pollution.
The story so far…
Till Dec 5th, GRAP-IV rules were in place in Delhi, which include the following measures:
- Restricted entry of trucks into Delhi, except those carrying essential items or using LNG, CNG, BS-VI diesel, or electric fuel.
- Ban on non-essential light commercial vehicles from outside Delhi, except for EVs and compliant CNG or BS-VI diesel vehicles.
- Prohibition on medium and heavy diesel goods vehicles registered in Delhi (BS-IV or older), except for essential services.
- Suspension of all construction activities, including public infrastructure projects like highways and pipelines.
- Conduct of online classes for all students including those in 10th and 12th standards.
- Advisory to offices in the NCR to operate at 50% capacity with remote work for the rest.
Additionally, under GRAP the State government can also close colleges, limit non-essential commercial activities, and implement odd-even vehicle rules to curb pollution.
The origin of the odd-even scheme
Introduced in Delhi by former Chief Minister Arvind Kejriwal in 2016, this scheme is a traffic rationing measure in which private cars with even-numbered registration plates are allowed on even dates, and those with odd-numbered plates on odd dates. This means vehicles ending with registration numbers 1, 3, 5, and 7 are permitted on odd days, while vehicles with 2, 4, 6, and 8 are allowed on even days.
This scheme has been implemented three times since its launch — in 2016, 2017, and 2019. The odd-even rule applies to all privately owned four-wheelers, with a long list of exemptions such as women drivers, vehicles carrying only women and children under 12 years, electric vehicles, and those driven by persons with disabilities.
The President, Vice-President, Prime Minister, Delhi’s Chief Minister, Lieutenant Governor, Chief Justice of India, and heads of key commissions like the Lokpal and Election Commission are exempt from the mandate. The odd-even scheme remains a part of Delhi’s pollution control strategy, implemented selectively as part of the GRAP during severe pollution episodes.
The odd-even experiment in other countries
Although introduced to India in 2016, the odd-even scheme had already been practised globally. Countries like China, France (Paris), Colombia (Bogotá), Mexico, and Italy experimented with it. In China, the rule was implemented ahead of the 2008 Olympics, resulting in nearly a 20% decrease in pollution levels. Alongside this scheme, efforts to improve public transport were also undertaken in the countries that implemented it. In Paris, for instance, public transport was free when the odd-even scheme was in place, encouraging people to leave their cars behind.
Odd-even rule: An emergency plan
“It is crucial to understand why such actions are taken,” says Anumita Roychowdhury, Executive Director at the Centre for Science and Environment. She explains that odd-even is an emergency action plan, not a year-round measure.
“Emergency measures are implemented during winter because severe smog episodes occur when existing pollution in the city gets trapped due to meteorological conditions like lack of wind. These conditions prevent pollutants from dispersing, leading to worsening air quality. Emergency actions, such as odd-even and even other measures under the GRAP, aim to minimise additional pollution sources. The goal is to prevent further deterioration of already critical conditions,” says Anumita.
In Delhi, there were reports of backlash to this scheme; a Business Standard article from 2023 reported that 64% of the people in Delhi NCR did not support the introduction of the odd-even scheme. Furthermore, 56% of those surveyed opposed one or more exemptions in the scheme.
Some citizens also faced challenges while using public transport when the scheme was implemented. Ashish Sharma, a resident of Delhi and a social worker, shared his experience from the time when the odd-even rule was in effect.
“The intention behind this initiative is good, but I faced several challenges when it was implemented. Using public transport, especially taking autos during this time, felt like being blackmailed. For the daily NGO service, where I used to distribute clothes using my car, the odd-even rule forced me to rely on private autos. I ended up paying ₹200–300 for a ride that usually costs around ₹150. It felt like auto drivers were taking advantage of us during this period, as we had no other options.,” said Ashish.
How the government backs the rule
When the Supreme Court questioned the scheme’s effectiveness, the Delhi government backed it with studies showing improvements in air quality. One study conducted by researchers from the University of Chicago, the Centre for Policy Research, and Harvard Kennedy School found that during the odd-even scheme in January 2016, PM2.5 levels dropped by an average of 13% between 8 am and 8 pm However, no measurable effect was noticed in April 2016 due to higher atmospheric dispersion during the warmer months.
A second study by IIT-Delhi, IIT-Kanpur, and other institutions showed that traffic restrictions from January 1–15, 2016, led to a 4–6% reduction in PM2.5 levels, with a peak decrease of up to 10% at certain pollution hotspots.
Traffic data from November 2019, when the scheme was in effect, indicated a 30% reduction in personal car usage. However, two-wheeler traffic increased by 6.5%, taxi usage rose by 19.5%, auto-rickshaw traffic by 7.5%, and bus usage by 4.7%.
Assessing the effectiveness of the odd-even scheme
“The issue lies in the data interpretation process,” explains Dr. Mohan P. George, Former Additional Director at the DPCC.
“Air quality measurements are conducted under dynamic conditions influenced by various meteorological factors. Since ambient air is a constantly moving mixture, accurately assessing its quality and the impact of interventions like the odd-even rule is beyond current scientific capabilities. The problem is not with the odd-even rule in itself — it effectively reduces emissions by taking 50% of cars off the road, as evidenced by lower fuel sales during the period. Instead, the limitation lies in the inadequacy of our current equipment and systems to measure its impact on ambient air quality accurately,” he adds.
If the government is convinced about the positive impact of the rule, why has it been implemented only thrice since 2016?
“A lot of people doubt the effectiveness of the odd-even rule, but it works, and we have multiple data studies to validate that,” says Jasmine Shah, Former Vice-Chairperson of the Dialogue and Development Commission of Delhi Government.
“Odd-even disrupts daily life, but we must remember that it is an emergency action plan, not a way of life. Implementing it too often might encourage people to buy more cars, as seen in Mexico, which would defeat the purpose. Every time we’ve implemented it, we’ve had public support. When the government takes tough calls to improve people’s lives, people rally behind it,” he added.
Odd-even rule: A band-aid solution?
“Odd-even is at best a band-aid on a wound that requires surgery,” says Radhika Jhaveri, a researcher and educator from Let India Breathe. She emphasises that the odd-even scheme does not address the root causes of air pollution. “Excessive construction and tree cutting, stubble burning, too many trucks, depletion of forest cover, thermal power plants, polluting industries, and waste burning — these are the key contributors, and none of them are being effectively addressed.”
Radhika reiterates that unless long-term measures are in place, not much will change. “The first step should have been to gradually transition to a car-free city. This could be achieved one step at a time, by creating car-free zones, exclusive bus lanes, and walking lanes. However, there are two major issues — apathy of the people, and the government’s lack of political will. The severity of the air pollution crisis we face today is a direct result of these two factors.”
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Desperate times call for desperate measures
“The time has come for Delhi to take drastic measures to reduce the use of private vehicles. Data from the Indian Institute of Tropical Meteorology shows that vehicle emissions contribute significantly to daily pollution. The reason is the sheer number of vehicles and traffic in the city,” says Anumita.
She emphasises the need for long-term solutions. “Delhi urgently needs to strengthen its public transport system, create zero-emission zones, and promote walking and cycling to cut down on personal vehicle usage. If car owners believe the city can clean its air without addressing private vehicle usage, they are mistaken. We must build public awareness and urge the government to provide an integrated public transport system to reduce dependency on personal cars,” she added.
On December 5th, the Supreme Court permitted the Commission for Air Quality Management to reduce GRAP Stage IV restrictions in Delhi to GRAP Stage II, considering the improvement in the city’s air quality.
Recommendations by experts to improve Delhi’s air quality
- Integrated public transport system to reduce dependency on private vehicles
- Transition towards a car-free city, one step at a time
- Exclusive bus lanes and walking lanes in the city
- Promoting walking and cycling among citizens
- Public consultation, awareness and building last-mile connectivity options