Fuel Efficiency & Emission Norms

In India, vehicle technology has evolved to meet the emission and safety regulations notified as per the Auto Fuel Policy specifying the emission road map and safety regulations adopted by the SCOE and CMVR-TSC, respectively. Today the vehicle technology in India is at par with the international benchmarks as Indian safety standards are being aligned with Global Technical Regulations (GTR) and UN Regulations. India is a signatory to UN WP 29 1998 agreement which develops GTRs. India actively participates in the UN WP 29 body and contributes significantly so that the GTR reflect the driving conditions and requirements of the developing countries.

India’s Automotive Industry Standards (AIS), developed by the Automotive Industry Standards Committee (AISC) under MoRTH, ensure alignment with global norms such as UNECE regulations.

In India, the adoption of alternate powertrains is a key pillar of the integrated approach to vehicular emission reduction. The Government of India has introduced multiple policy interventions, such as the National Electric Mobility Mission Plan (NEMMP), Faster Adoption and Manufacturing of Electric Vehicles (FAME), and the National Bio-Energy and Hydrogen Missions, to promote electric, hybrid, CNG, LNG, biofuel, and hydrogen-based vehicles. These powertrains offer significant potential to reduce tailpipe emissions and fossil fuel dependence, particularly in urban and high-usage segments. Regulatory frameworks under CMVR and standards notified by MoRTH, BIS, and ARAI are being progressively updated to accommodate new technologies while ensuring safety, performance, and interoperability. India is also aligning powertrain-related regulations with global best practices to enable technology transfer, domestic manufacturing, and long-term decarbonization of the transport sector.

The use of light-weight materials is an important enabler for improving vehicle efficiency and reducing emissions across all powertrains. By reducing vehicle mass, fuel consumption and energy demand per kilometre can be significantly lowered, leading to reduced CO₂ and pollutant emissions. In India, OEMs are increasingly adopting advanced high-strength steels, aluminium alloys, polymers, composites, and engineered plastics while ensuring compliance with safety and crashworthiness regulations. Automotive standards and material specifications notified under AIS, BIS, and CMVR provide a regulatory framework for the safe adoption of such materials. India’s vehicle safety regulations, aligned with UN and GTR norms, ensure that weight reduction does not compromise occupant safety. Continued innovation in materials and manufacturing processes is critical to achieving emission reduction targets while maintaining affordability and structural integrity.

It was in 1996 that the Ministry of Environment and Forests formally notified fuel specifications. Maximum limits for critical ingredients such as benzene level in petrol has been reduced continuously, from time to time, and was specified as 5% m/m and 3% m/m pa India and metros, respectively. This limit now stands at 1%, which is in line with international practices.

To address the high pollution in metro cities, 0.05% sulphur for petrol and diesel has been introduced in 2000-2001. The same has been reduced to 0.005% in April 2010 in 13 metro cities for both petrol and diesel.. For the rest of the country, the limit on sulphur content for diesel and petrol is 350 ppm and 150 ppm, respectively.

The improvement in the fuel quality from BS-IV to BS-VI was achieved by reducing the sulphur content from 50 Parts Per Million (ppm) in BS-IV to maximum 10 ppm in BS-VI compliant fuel. This has facilitated the development of upgraded / improved engine technologies such as introduction of advanced emission control system, installation of catalytic convertor or diesel particulate filters to reduce particulate matter and selective catalyst reduction systems for reduction in Nitrogen Oxides emissions in BS-VI compatible vehicles.

Inspection & Maintenance (I&M) of all categories of vehicles is one of the important tool controlling emissions ensuring roadworthiness and monitoring the health of in-use vehicles. The I&M programme in India consists of mandatory periodic PUC certifications for all types of vehicles and annual fitness certifications for commercial vehicles.

According to the Central Motor Rules 1989, every motor vehicle is mandated to carry a valid PUC certificate after one year from the date of first registration. Two types of tests are performed depending on the type of engine—diesel engine or petrol/CNG/LPG engine. The detailed procedures for the emission testing for both types of vehicles are prescribed in the CMVR of 1989.

The gasoline/CNG/LPG vehicles are tested for CO and HC emissions, and lambda values and the diesel vehicles are tested for Hartridge Smoke Units (HSU), a standard for testing diesel engine exhaust emission. The standards for in-use vehicles in India were prescribed under Rule 115 (2) of Central Motor Vehicles Rules 1989, under the Motor Vehicles Act 1988. Revised PUC norms for in-use vehicles were notified by Ministry of Road Transport and Highways, Government of India, which were implemented across the country from November, 2019, included BS IV Norms.

Globally, Inspection & Maintenance (I&M) of in-use vehicles has emerged as a core policy tool to control vehicular emissions. Developed regions such as the European Union, Japan, United States, Canada, and Australia have long-established periodic vehicle inspection regimes covering emissions and roadworthiness . China significantly strengthened its national I&M framework in 2020, mandating inspection-linked repair and compliance for high-emitting vehicles . Several Latin American cities such as Mexico City and Sao Paulo operate mandatory emissions inspection programs as part of urban air-quality management . In South-East Asia, countries including Thailand, Vietnam, and Indonesia are transitioning towards more comprehensive I&M systems to address worsening air quality. Emerging economies in Africa are at planning or pilot stages, supported by institutions such as the World Bank and WHO, recognising I&M as critical for managing in-use vehicle emissions"

With roads as one of the dominant modes of transport carrying about 60% of freight and 87% of passenger traffic coupled with limited road space, different types of vehicles, i.e. 2- wheelers, 3-wheeler or 4-wheelers motorized and non motorized vehicles sharing the single road lead to traffic congestion, delay in travel time, air pollution and accidents. To make the transport system effective and efficient, there is a need that each mode of transport should be connected to each other. For that it is not only the vehicle which needs to be smart, but infrastructure also is required to be intelligent to enable interaction between various modes of transport.

Intelligent Transport System – enables smooth flow of traffic and reduces GHG emissions through its various applications like real time traffic information system, collision avoidance system, vehicle to vehicle and vehicle to infrastructure communications etc.

ITS is an integration of computer, electronics and communication technologies. It enables exchange of information for better management and use of available resources, by providing real-time travel and traffic information, transit routes, schedules, navigation directions, weather conditions etc., and thus facilitates smooth flow of traffic and improved mobility on congested corridors, while makingthem safer and hence reducing congestion, environmental emissions and fuel usage.

AIS -140 is the Standard notified by MoRTH, Govt of India in 2017, for vehicle tracking and emergency management. The same has been mandated for public and commercial (taxis) transport with effect from April 2018.

Corporate Average Fuel Efficiency (CAFÉ) norms were first notified by the Government in 2017, under the Energy Conservation Act, 2001 to mitigate fuel consumption by lowering CO₂ emissions; aiming to reduce oil dependency and air pollution. These norms are applicable for petrol, diesel, liquefied petroleum gas (LPG), CNG, hybrid, and electric passenger vehicles with gross vehicle weight (GVW) < 3500kgs.

It relates the gasoline equivalent corporate average fuel consumption (in litres/100 km) to the corporate average kerb weight of all the cars sold by any original equipment manufacturer (OEM) in a fiscal year. The corporate average fuel consumption is estimated by averaging the standard fuel consumption of all vehicles sold each year. This fuel consumption is measured under standard conditions in nationally accredited labs. There is a limit set on the total emission of CO₂ emitted, as the amount of CO₂ a car emits has a direct correlation with the amount of fuel it consumes.

These standards were introduced in two phases—the first CAFE norms stage I fuel consumption standards were introduced effective 2017–18, and the CAFE norms stage II standards came into force in 2022–23.