India: Heavy-Duty Truck and Bus Engines

Emission Standards
OBD Requirements

Emission Standards

Emission standards for new heavy-duty onroad engines—applicable to vehicles of GVW > 3,500 kg—are listed in Table 1. Limits for BS V shown in Table 1 were proposed in November 2015 [3297][3298] but later removed from an updated proposal [3349]; transitioning the nation directly to BS VI from BS IV.

**Table 1**
Emission standards for hevy-duty engines
Stage	Year	Test	CO	HC	CH₄	NOx	PM	PN	NH₃
Stage	Year	Test	g/kWh					kWh^-1	ppm
	1992	ECE R49	17.3	2.7		-	-
	1996	ECE R49	11.2	2.4		14.4	-
India 2000	2000	ECE R49	4.5	1.1		8.0	0.36^a
BS II	2005†	ECE R49	4.0	1.1		7.0	0.15
BS III	2010†	ESC	2.1	0.66		5.0	0.10
BS III	2010†	ETC	5.45	0.78		5.0	0.16
BS IV	2010‡	ESC	1.5	0.46		3.5	0.02
BS IV	2010‡	ETC	4.0	0.55		3.5	0.03
BS V	n/a ^b	ESC	1.5	0.46		2.0	0.02
BS V	n/a ^b	ETC	4.0	0.55	1.1^d	2.0	0.03
BS VI	2020^c	WHSC (CI)	1.5	0.13		0.40	0.01	8.0×10¹¹	10
		WHTC (CI)	4.0	0.16		0.46	0.01	6.0×10¹¹^e	10
		WHTC (PI)	4.0	0.16^f	0.50	0.46	0.01	6.0×10¹¹^e	10
† earlier introduction in selected regions, see India: Table 1 ‡ only in selected regions, see India: Table 1 ^a 0.612 for engines below 85 kW ^b Initially proposed in 2015.11 [3297][3298] but removed from a 2016.02 proposal [3349] ^c Proposed schedule and limits ^d For CNG engines only ^e Applicable from April 1, 2025 for new models and April 1, 2026 for existing models ^f NMHC

Stage VI (Euro VI) gasoline engines are certified with E10 and diesel engines with B7. In-use compliance test procedures for BS VI engines are defined in an Automotive Industry Standard (AIS-137) to be published by the Automotive Research Association of India. The maximum in-use conformity factor for CO, THC, NMHC, CH4 and NOx is 1.50. A PEMS test at type approval for vehicles with BS VI engines is also required. Off-cycle limits following the WNTE cycle must also be met.

In November 2015, a draft proposal was published that required vehicles compatible with biodiesel blends up to B100 to certify with both diesel fuel and B100 (see India: Table 2).

OBD Requirements

Proposed OBD requirements are similar to those for Europe. Table 2 summarizes the phase-in schedule [3298].

**Table 2**
OBD threshold limits (OTL)
Stage	Year	Vahicle Category	NOx	CO	PM
Stage	Year	Vahicle Category	g/kWh
BS V	n/a ^a	All	7.0		0.1^d
BS VI	2020^b	CI engines	1.5		Performance monitoring
BS VI	2020^b	Gas engines†	1.5		-
BS VI	2026^c	CI engines	1.2		0.025^e
BS VI	2026^c	Gas engines†	1.2	7.5^e	-
^a Initially proposed in 2015.11 [3297][3298] but removed from a 2016.02 proposal [3349] ^b For new models, 2021 for existing models ^d CI engines only ^e Limit to be reviewed at a later date † All gas fueled engines and PI engines fitted to vehicles category M₃, to N₂ vehicles having a maximum permissible mass > 7.5 tonnes, and to N₃ vehicles

More details on Euro I-VI regulations and testing requirements can be found in the EU heavy-duty engine standards page.