ExplainedAir pollution
BS-IV ban explained: what Bharat Stage norms are, and which vehicles Delhi has shut out
From Sunday, BS-IV and older vehicles registered outside Delhi are barred from the capital, and a year-long grace period for BS-IV trucks has run out. What the BS numbers mean, how to tell where your vehicle stands, and how these curbs differ from GRAP.
The short answer
Bharat Stage (BS) norms are India's emission standards for vehicles, modelled on European rules; the higher the number, the cleaner the engine and fuel. India moved from BS-IV in 2017 straight to BS-VI in April 2020, skipping BS-V. From 1 November 2026 the Delhi government has barred vehicles registered outside Delhi that meet BS-IV or older standards until 31 January, and a CAQM direction that let outside BS-IV commercial goods vehicles into the city until 31 October 2026 has lapsed. Delhi-registered vehicles, BS-VI vehicles and those running on CNG, LNG or electricity are not covered by the entry ban.
What changed on Sunday?
Two sets of rules met at midnight. The first is a Delhi government package that came into force on 1 November: vehicles registered outside Delhi that meet BS-IV or older emission standards can no longer run in the capital until 31 January. Offices must keep physical attendance at half, dusty building work has stopped and parking costs double. CNG and electric vehicles, ambulances, fire tenders and police vehicles are exempt.
The second is older and aimed at trucks. On 1 November 2025 the Commission for Air Quality Management (CAQM) barred commercial goods vehicles registered outside Delhi unless they were BS-VI, CNG, LNG or electric. BS-IV goods vehicles were given a transitional window until 31 October 2026. That window closed on Saturday night, so an outside BS-IV truck that could enter Delhi last week cannot enter it now.
Chief Minister Rekha Gupta asked residents to cooperate. “Do not bring restricted vehicles registered outside Delhi into the city,” she said.
What does BS actually stand for?
Bharat Stage, India’s version of Europe’s emission standards. The central government sets limits on how much carbon monoxide, nitrogen oxides (NOx), unburnt hydrocarbons and fine particulate matter a new vehicle’s engine may emit, and on how much sulphur the fuel may contain. Each new stage tightens those limits, and carmakers must redesign engines and exhaust systems to meet them.
The first stage arrived in 2000. BS-III became the national standard in 2010 and BS-IV in April 2017. Then the government did something unusual: it skipped BS-V altogether and jumped to BS-VI on 1 April 2020, under a Road Transport Ministry notification of February 2016.
In 2018 the Supreme Court refused the government’s request for a grace period and ordered that from 1 April 2020 only BS-VI vehicles could be sold or registered anywhere in India, including two-wheelers, three-wheelers and commercial vehicles.
How India's vehicle emission rules tightened
- 2000Bharat Stage norms introduced, based on Euro I; BS-II in the National Capital Region.
- 2010BS-III becomes the national standard.
- Feb 2016Road Transport Ministry notifies a direct jump to BS-VI, skipping BS-V.
- Apr 2017BS-IV comes into force across the country.
- Apr 2020BS-VI takes effect; only BS-VI vehicles can be sold or registered.
- Nov 2025CAQM bars outside non-BS-VI goods vehicles from Delhi, with BS-IV allowed for one more year.
- Nov 2026BS-IV window ends; Delhi also bars outside BS-IV and older vehicles until 31 January.
How much cleaner is BS-VI than BS-IV?
Much cleaner, especially for diesel. BS-IV fuel may carry up to 50 parts per million of sulphur; BS-VI fuel carries no more than 10. For diesel cars, BS-VI cuts the permitted NOx by about 68% and particulate matter by about 82%. For petrol cars the NOx limit falls by about 25%. Diesel engines are the bigger concern in Delhi because of the soot and NOx they produce, which is why trucks and older diesel cars are the first to be pushed off the road when the air turns bad.
BS-IV against BS-VI
How do I know my vehicle’s BS standard?
Start with the registration date. Because of the Supreme Court’s order, almost any vehicle first registered after April 2020 is BS-VI. Vehicles registered between April 2017 and March 2020 are mostly BS-IV, and older ones are BS-III or below. The registration certificate usually states the emission norm as well. If your car or truck is registered in Delhi, the entry ban does not apply to you, though the separate rule against diesel vehicles older than 10 years and petrol vehicles older than 15 years in the NCR still does.
Why target vehicles from outside Delhi?
Because Delhi cannot control what is registered next door. A heavy stream of diesel trucks crosses into the city every day, and officials said last year that about 40% of those entering carry essential supplies. CAQM issued its truck rule as a statutory direction under its 2021 law, saying the aim was to cut pollution from that daily flow. Transporters pushed back then. “The Supreme Court had given the orders,” said Rajendra Kapoor of the All India Motor and Goods Transport Association, adding that if they wanted the BS-IV curbs lifted after a year, “we will have to approach the court.”
Is this the same as GRAP?
No. These curbs run on fixed dates, whatever the air quality. The Graded Response Action Plan is CAQM’s emergency ladder, switched on stage by stage as the Air Quality Index worsens. At Stage III, for instance, BS-III petrol and BS-IV diesel cars are kept off the roads across Delhi and nearby districts. The new rules sit underneath that ladder: GRAP’s curbs on goods vehicles still apply on top whenever a stage is in force.
How will it be enforced?
By cameras and automatic fines. Number-plate recognition cameras and the Integrated Command and Control Centre will track vehicles, and those that break the ban will get automatic e-challans and may be impounded, the Delhi government said. The Transport Department, the Delhi Traffic Police, the Delhi Pollution Control Committee and the Municipal Corporation share the job. The real test comes at the borders, where stakeholders warned last year that turning back non-compliant trucks could choke traffic.