Emissions from new diesel engines used in generator sets have been regulated by the Ministry of Environment and Forests, Government of India. The regulations impose type approval testing, production conformity testing and labeling requirements. The regulations also include a list of authorized agencies for type approval testing.
Engines up to 800 kW. Emission limits for new diesel engines ≤ 800 kW used in genset applications were set in 2002  and strengthened in 2013 . The regulations also set noise limits for diesel generator sets up to 1000 kVA.
The emission standards are listed below. Table 1 summarizes the standards that became applicable in 2004/2005, and Table 2 lists the strengthened limits applicable from April 2014.
|Engine Power (P)||Date||CO||HC||NOx||PM||Smoke|
|P ≤ 19 kW||2004.01||5.0||1.3||9.2||0.6||0.7|
|19 kW < P ≤ 50 kW||2004.01||5.0||1.3||9.2||0.5||0.7|
|50 kW < P ≤ 176 kW||2004.01||3.5||1.3||9.2||0.3||0.7|
|176 kW < P ≤ 800 kW||2004.11||3.5||1.3||9.2||0.3||0.7|
|Engine Power (P)||Date||CO||NOx+HC||PM||Smoke|
|P ≤ 19 kW||2014.04||3.5||7.5||0.3||0.7|
|19 kW < P ≤ 75 kW||2014.04||3.5||4.7||0.3||0.7|
|75 kW < P ≤ 800 kW||2014.04||3.5||4.0||0.2||0.7|
Engines are tested over the 5-mode ISO 8178 D2 test cycle. Smoke opacity must not exceed the limits at full load (Table 1) or at any load point of the test cycle (Table 2). The same limits are applicable for type approval and for conformity of production (COP) testing.
Engines above 800 kW. Emission standards for new diesel engines above 800 kW used in genset applications were phased-in between 2003 and 2005, Table 3 .
|2003.07 - 2005.06||150||100||970 (710a)||75c|
a For engines in plants of total power rating above 75/150 MW located in urban/rural areas, respectively.|
b 150 mg/Nm3 for engines fueled with furnace oil.
c 100 mg/Nm3 for engines fueled with furnace oil.
Concentrations are corrected to dry exhaust conditions at 15% residual O2.