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 1990’s. Since the year 2000, India started adopting European emission and fuel regulations for four-wheeled light-duty and for heavy-duty vehicles. Indian own emission regulations still apply to two- and three-wheeled vehicles.

On October 6, 2003, the National Auto Fuel Policy has been announced, which envisages a phased program for introducing Euro 2 – 4 emission and fuel regulations by 2010. The implementation schedule of EU emission standards in India is summarized in Table 1.

The above standards apply to all new 4-wheel vehicles sold and registered in the respective regions. In addition, the National Auto Fuel Policy introduces certain emission requirements for interstate buses with routes originating or terminating in Delhi or the other 10 cities.

For 2-and 3-wheelers, Bharat Stage II (Euro 2) will be applicable from April 1, 2005 and Stage III (Euro 3) standards would come in force preferably from April 1, 2008, but not later than April 1, 2010.

Trucks and Buses

Emission standards for new heavy-duty diesel engines—applicable to vehicles of GVW > 3,500 kg—are listed in Table 1. Emissions are tested over the ECE R49 13-mode test (through the Euro II stage).

More details on Euro I-III regulations can be found in the EU heavy-duty engine standards page.

Light Duty Diesel Vehicles

Emission standards for light-duty diesel vehicles (GVW ≤ 3,500 kg) are summarized in Table 3. Ranges of emission limits refer to different classes (by reference mass) of light commercial vehicles; compare the EU light-duty vehicle emission standards page for details on the Euro 1 and later standards. The lowest limit in each range applies to passenger cars (GVW ≤ 2,500 kg; up to 6 seats).

The test cycle has been the ECE + EUDC for low power vehicles (with maximum speed limited to 90 km/h). Before 2000, emissions were measured over an Indian test cycle.

Engines for use in light-duty vehicles can be also emission tested using an engine dynamometer. The respective emission standards are listed in Table 4.

Light Duty Gasoline Vehicles

4-Wheel Vehicles

Emission standards for gasoline vehicles (GVW ≤ 3,500 kg) are summarized in Table 5. Ranges of emission limits refer to different classes of light commercial vehicles (compare the EU light-duty vehicle emission standards page). The lowest limit in each range applies to passenger cars (GVW ≤ 2,500 kg; up to 6 seats).

Gasoline vehicles must also meet an evaporative (SHED) limit of 2 g/test (effective 2000).

3- And 2-Wheel Vehicles

Emission standards for 3- and 2-wheel gasoline vehicles are listed in the following tables.

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Construction Machinery

Emission standards for diesel construction machinery were adopted on 21 September 2006. The standards are structured into two tiers:

• Bharat (CEV) Stage II—These standards are based on the EU Stage I requirements, but also cover smaller engines that were not regulated under the EU Stage I.
• Bharat (CEV) Stage III—These standards are based on US Tier 2/3 requirements.

The standards are summarized in the following table:

The limit values apply for both type approval (TA) and conformity of production (COP) testing. Testing is performed on an engine dynamometer over the ISO 8178 C1 (8-mode) and D2 (5-mode) test cycles.

The Bharat Stage III standards must be met over the useful life periods shown in Table 2. Alternatively, manufacturers may use fixed emission deterioration factors of 1.1 for CO, 1.05 for HC, 1.05 for NOx, and 1.1 for PM.

Agricultural Tractors

Emission standards for diesel agricultural tractors are summarized in Table 3.

Emissions are tested over the ISO 8178 C1 (8-mode) cycle. For Bharat (Trem) Stage III A, the useful life periods and deterioration factors are the same as for Bharat (CEV) Stage III, Table 2.

Generator Sets

Emissions from new diesel engines used in generator sets have been regulated by the Ministry of Environment and Forests, Government of India [G.S.R. 371 (E), 17 May 2002]. The regulations impose type approval certification, production conformity testing and labeling requirements. Certification agencies include the Automotive Research Association of India and the Vehicle Research and Development Establishment. The emission standards are listed below.

Engines are tested over the 5-mode ISO 8178 D2 test cycle. Smoke opacity is measured at full load.

Concentrations are corrected to dry exhaust conditions with 15% residual O₂.