The first Indian emission regulations were idle emission limits which became effective in 1989. These idle emission regulations were soon replaced by mass emission limits for both gasoline (1991) and diesel (1992) vehicles, which were gradually tightened during the 1990s. Since the year 2000, India started adopting European emission and fuel regulations for four-wheeled light-duty and for heavy-duty vehicles. India’s own emission regulations still apply to two- and three-wheeled vehicles.
The foundation for automotive emission standards in India since the early 2000s is contained in two reports from the Indian Planning Commission. The National Auto Fuel Policy, announced on October 6, 2003, envisioned a phased program for introducing Euro 2-4 emission and fuel regulations by 2010. In order to establish limits beyond Bharat Stage IV, the Indian Planning Commission established an Expert Committee in 2013 to draft an updated Auto Fuel Policy, Auto Fuel Vision and Policy 2025, that was published in May 2014. While legislators are not required to adhere strictly to the recommendations contained in these reports, they serve as a starting point for subsequent legislative action to establish the implementation schedule and other details of automotive emission standards. The implementation schedule of EU emission standards in India is summarized in Table 1.
|India 2000||Euro 1||2000||Nationwide|
|Bharat Stage II||Euro 2||2001||NCR*, Mumbai, Kolkata, Chennai|
|2003.04||NCR*, 11 cities†|
|Bharat Stage III||Euro 3||2005.04||NCR*, 11 cities†|
|Bharat Stage IV||Euro 4||2010.04||NCR*, 13 cities‡|
|2015.07||Above plus 29 cities mainly in the states of Haryana, Uttar Pradesh, Rajasthan and Maharastra |
|2015.10||North India plus bordering districts of Rajasthan (9 States) |
|2016.04||Western India plus parts of South and East India (10 States and Territories) |
|Bharat Stage V||Euro 5||n/a a|
|Bharat Stage VI||Euro 6||2020.04||Nationwide |
|* National Capital Region (Delhi)|
† Mumbai, Kolkata, Chennai, Bangalore, Hyderabad, Secunderabad, Ahmedabad, Pune, Surat, Kanpur and Agra
‡ Above cities plus Solapur and Lucknow. The program was later expanded with the aim of including 50 additional cities by March 2015
a Initially proposed in 2015.11  but removed from a 2016.02 proposal 
The above standards apply to all new 4-wheel vehicles sold and registered in the respective regions. In addition, the National Auto Fuel Policy 2003 introduced certain emission requirements for interstate buses with routes originating or terminating in Delhi or the other mentioned cities.
For 2-and 3-wheelers, Bharat Stage II applied from April 1, 2005 and Stage III standards came into force in April 1, 2010. Bharat Stage IV standards for gasoline fueled 2-wheelers came into force April 1, 2016. Bharat Stage VI standards for SI and CI 2- and 3-wheelers were proposed in February 2016.
The roll out of Bharat Stage IV limits nationwide was delayed by the challenge of convincing fuel producers to make the necessary investments required to supply 50 ppm sulfur fuel nationwide. Potential solutions that have been suggested include deregulation of diesel prices, an environment compensation charge on diesel vehicles and an additional levy on diesel fuel.
Even in cities with Bharat Stage IV limits, there have been challenges ensuring the dominance of compliant vehicles. Some of these challenges include: exemptions granted to some specialty vehicle (e.g., taxis) manufacturers, registration of Bharat Stage III vehicles by vehicle owners outside of their place residence due to loopholes in residential proof, registration of commercial vehicles outside of the Bharat Stage IV zones and insufficient availability of some specialty vehicles (e.g., garbage trucks) in Bharat Stage IV configurations.
In its May 2014 report, Auto Fuel Vision and Policy 2025, the Expert Committee recommended that Bharat Stage IV fuel be required nationwide from April 2017 followed by a further step up to the BS V in April 2020 and BS VI in April 2024. Draft recommendations discussed prior to the report’s release included a national Bharat Phase IV+ stage (40 ppm sulfur) starting in 2017 and a national Bharat Stage V fuel standard staring in 2021. The Oil Ministry supported proceeding directly from BS IV to BS VI but this was opposed by the automotive industry. In November 2015, a draft notice was published by the Ministry of Road Transport and Highways announcing that BS V would be implemented across the country starting 2019 and BS VI starting 2021. While the automotive industry was supportive of the dates for BS V, they claimed advancing the dates for BS VI by more than 1 year from those recommended by the Expert Committee would not leave sufficient time for testing and validation and were unrealistic.
Severe air pollution episodes at the end of 2015 in Delhi-NCR lead to a number of Supreme Court rulings that would have significant impacts on the automotive industry. One ruling in late 2015 banned the sale of diesel cars in the NCR with engine displacements greater than 2.0 L from January 1 to April 1, 2016. Another ruling in early January 2016 asked the government to advance the implementation of BS VI emission standards from those contained in the November 2015 proposals. The government responded by withdrawing its November 2015 BS V/VI proposal and announcing that they would move the implementation date for BS VI to April 1, 2020 for all models and skip over BS V standards. A new draft proposal was published in February 2016.
Biodiesel Testing. In November 2015, a draft notification was published that, if passed, would require all newly produced vehicles compatible with diesel or a mixture of diesel and biodiesel up to B100 (flex-fuel biodiesel vehicle) to meet emission standards with both diesel and B100 reference fuels. Proposed requirements are listed in Table 2. Diesel vehicles compatible with blends up to B20 would only need to certify with diesel fuel .
|Test||4 wheeled vehicles with GVW ≤ 3,500 kg||3 wheeled vehciles||4 wheeled vehicles with GVW > 3,500 kg|
|Gaseous pollutants||Both diesel and B100||Both diesel and B100||Both diesel and B100|
|Free acceleration smoke||Both diesel and B100||Both diesel and B100||Both diesel and B100|
|Durability, if opted for instead of fixed Deterioration Factor||Diesel fuel only||Diesel fuel only||Diesel fuel only|
|OBD||Both diesel and B100||Not applicable||Both diesel and B100|
Fuel Economy. Attempts to set fuel economy standards started in 2007, but it were delayed due to inter-ministerial conflicts and pressure from the automobile industry. In January 2014, the Ministry of Power the Bureau of Energy Efficiency notified minimum fuel efficiency norms for passenger vehicles that are sold in India. Two sets of standards were announced: one set for fiscal years 2016-17 to 2020-21 and another for fiscal year 2021-22 onwards . The Road Transport Ministry objected by claiming the new emission levels were being mandated a year ahead of an earlier agreed to deadline.
Regulated Engines and Vehicles
Emission standards and fuel economy regulations have been adopted for the following categories of new engines and/or vehicles: