On February 19, 2016, the Indian Ministry of Road Transport and Highways (MoRTH) issued a draft notification of Bharat Stage (BS) VI emission standards for all major on-road vehicle categories in India. The standards apply to light- and heavy duty vehicles, as well as two- and three-wheeled vehicles. As proposed, the BS VI standards will go into effect for all vehicles in these categories manufactured on or after April 1, 2020. The draft BS VI proposal specifies mass emission standards, type approval requirements, and on-board diagnostic (OBD) system and durability levels for each vehicle category and sub-classes therein. In addition, reference and commercial fuel specifications are included in the BS VI proposal. The adoption of the proposed BS VI emission standards will essentially bring Indian motor vehicle regulations into alignment with European Union regulations for light-duty passenger cars and commercial vehicles, heavy-duty trucks and buses, and two-wheeled vehicles. While not yet reaching European levels, more stringent emission standards are also set for three-wheeled vehicles.
With this proposal, the Indian Government has confirmed its intent to leapfrog BS V level emission standards and move directly to the more stringent and robust BS VI level. The proposed BS VI standards are far-reaching in scope and incorporate substantial changes to existing Bharat Stage III and IV emission standards. Of particular note is the tightening of particulate matter (PM) mass emission limits and the introduction of particle number (PN) limits for light- and heavy-duty vehicles (LDV, HDV) fitted with gasoline direct injection (GDI) and compression ignition (CI), or diesel, engines. As evidenced by the adoption of nominally equivalent PM and PN standards in Europe, this step will likely lead to the near-universal application of diesel particulate filters (DPF) to control PM emissions from new diesel LDVs and HDVs. A second important component of the BS VI standards is the expansion of type approval and in-service conformity test requirements for LDVs and HDVs. For LDVs, provisions are included in the BS VI proposal for real-world driving cycle emission measurements using portable emissions measurement systems (PEMS). For HDVs, the European Stationary Cycle (ESC) and European Transient Cycle (ETC) used for BS III and IV type approval are replaced with the World Harmonized Steady-State Cycle (WHSC) and World Harmonized Transient Cycle (WHTC), respectively. The WHSC and WHTC are more representative of real-world driving conditions and better capture driving modes in which pollutant emissions can be elevated. In addition, off-cycle emissions testing requirements and in-service conformity testing for type approval and in-service vehicles using PEMS are introduced for HDVs in the BS VI proposal. For both LDVs and HDVs, these requirements will help to ensure that emissions performance demonstrated in laboratory testing is also maintained under real-world driving conditions.
Additional noteworthy aspects of the BS VI proposal include enhanced OBD requirements for all vehicle classes, with first-ever OBD specifications for two- and three-wheeled vehicles, and the introduction of emission limits on nitrogen oxides (NOX), carbon monoxide (CO), and hydrocarbon (HC) for two-wheelers that are equivalent to proposed BS VI norms for light-duty gasoline passenger vehicles. This step will ensure that BS VI two-wheelers will be as clean as BS VI gasoline passenger vehicles on a per-kilometer-driven basis.