India: Fuels: Diesel and Gasoline

India: Fuels: Diesel and Gasoline

Overview

Beginning in 2020, India required on-road diesel and gasoline nationwide to meet Bharat Stage (BS) VI specifications (maximum 10 ppm sulfur).

Standard type
Fuel quality
Applicability
All gasoline and diesel fuel

History

In India, fuel quality standards have been designed and implemented in conjunction with complimentary vehicle emissions standards. India’s fuel quality standards have been gradually tightened since the mid 1990s. Low-lead gasoline was introduced in 1994 in Delhi, Mumbai, Kolkata, and Chennai. In 2000, unleaded gasoline was mandated nationwide. India has adopted the European template for vehicle emissions and fuel quality standards, and the standards are termed as Bharat Stages (BS) In other words, Bharat Stage III standards are equivalent to Euro 3 standards.

After lead, sulfur content is the second most important determiner of fuel quality. Sulfur inhibits the proper functioning of aftertreatment systems designed to reduce tailpipe emissions and corrodes engines and pipes. The effect of fuel sulfur content is particularly damaging to three types of aftertreatment systems: diesel particulate filters (DPFs), lean NOx traps (LNTs), and selective catalytic reduction (SCR).

Bharat Stage VI

In 2016, the Ministry of Road Transport and Highway issued a draft notification of BS VI emission standards, equivalent to Euro VI. In April 2020, the standards took effect throughout the country for all light- and heavy-duty vehicles, as well as two- and three-wheelers manufactured. The BS VI standard specifies 10 ppm sulfur for both gasoline and diesel fuels. In conjunction with the proposed BS VI emission standard, the Ministry of Petroleum and Natural Gas (MoPNG) announced a nationwide supply of BS VI fuel would be available . The BS VI regulation established an important precedent by changing directly from Euro IV-equivalent to Euro VI-equivalent motor vehicle emission standards and fuels, skipping the Euro V stage.

Legislative background

In India, the legal foundation for enforcing automotive fuel standards is based on several laws:

  • The Essential Commodities Act (1955) gives state governments the right to ensure that all essential commodities, including petroleum products, are easily available to the public and meet government standards. For those who violate the act, it calls for fines, imprisonment for up to one year, and forfeiture of the right to do business in India.
  • The Air (Prevention and Control of Pollution) Act (1981) gives State Pollution Control Boards (SPCBs) the right to prohibit the production or burning of any fuel that is determined to lead to air pollution.
  • The Environment (Protection) Act (1986) does not specifically mention fuels but does authorize the central and the state governments to regulate activities that can harm the environment, under which the burning of fossil fuels could be included, depending on the interpretation.
  • The Petroleum Rules (2002) lists specific guidelines to be followed for the importation and/or refinement of fuel in India, and the transport of fuel within the country.
  • The Petroleum and Natural Gas Regulatory Board Act (2006) created the Petroleum and Natural Gas Regulatory Board (PNGRB) under MoPNG, and is responsible for ensuring fuel quality standards, from import and production through retail sales. PNGRB is charged with ensuring that the PNGR rules are followed. PNGRB is also authorized to resolve all disputes among producers, transporters, retailers, and consumers over fuel-related issues, and has the legal authority to enforce fuel quality standards at retail outlets.

Technical Standards

Fuel Sulfur Content

The sulfur content of diesel fuel is of particular interest in India due to historical diesel fuel subsidies that have contributed to a large number of diesel light-duty vehicles on the road as well as heavy-duty vehicles. The following table indicates the timeline of fuel sulfur content reductions in India, including expected reductions with the proposed BS VI standards:

Implementation of fuel sulfur content reductions in India
Date Diesel Gasoline
1995 10,000 ppm (nationwide)
1996 5,000 ppm (Delhi + selected cities)
1998 2,500 ppm (Delhi)
1999 500 ppm (BS II, Delhi, limited supply)
2000 2,500 ppm (nationwide)
2001 500 ppm (BS II, selected cities)
2005 500 ppm (BS II, nationwide)
350 ppm (BS III, selected cities)
500 ppm (BS II, nationwide)
150 ppm (BS III, selected cities)
2010 350 ppm (BS III; nationwide)
50 ppm (BS IV; selected cities)
150 ppm (BS III, nationwide)
50 ppm (BS IV, selected cities)
2017 50 ppm (BS IV;nationwide) 50 ppm (BS IV; nationwide)
2020 10ppm (BS VI; nationwide) 10 ppm (BS VI; nationwide)

Diesel

Following the European regulatory pathway with a lag of several years, India fuel quality and vehicle emissions standards requirements have usually been first introduced in Delhi and other major cities, followed by nationwide implementation. The evolution of diesel fuel quality is summarized in the table below. India has reduced its diesel sulfur content from 10,000 ppm in most of the country in 1999 to a maximum content of 350 ppm in 2012. During this same time period, India reduced diesel sulfur content from 2,500 ppm to 50 ppm in thirteen major metropolitan areas. Another factor that improved over this period was the cetane number, which increased from 45 to 51 nationwide over a period of 13 years.

The BS VI regulation reduced diesel sulfur content to a maximum of 10 ppm, enabling the introduction of advanced emission control technologies, including diesel particulate filters (DPF) and selective catalytic reduction (SCR) systems, which are both needed to meet BS VI emission standards.

Indian diesel specification required meeting Bharat Stage II, III, & IV emission norms
Characteristics Unit Bharat Stage II Bharat Stage III Bharat Stage IV Bharat Stage VI
Implementation date 2001 (selected cities), 2005 (nationwide) 2005 (selected cities), 2010 (nationwide) 2010 (selected cities), 2017 (nationwide) 2020(nationwide)
Ash, max  % mass 0.01 0.01 0.01 0.01
Carbon Residue (Ramsbottom) on 10% residue, maxa  % mass 0.3 0.3 0.3 0.3
Cetane Number (CN), min 48b 51 51 51
Cetane Index (CI), min 46b 46 46 46
Distillation 95% vol. Recovery at °C, max °C 360 360 370
Flash point Abel, min °C 35 35 35 35
Kinematic Viscosity at 40 °C cst 2.0–5.0 2.0-5.0 2.0–4.5 2–4.5
Density at 15 °C Kg/m3 820–860 (820–870)b 820–845 820–845 820–860
Total Sulfur, max mg/kg 500 350 50 10
Water content, max mg/kg 0.05% vol 200 200 200
Cold filter plugging point (CFPP)
a) Summer, max
b) Winter, max
°C
°C
18
6
18
6
18
6
18
6
Total contaminations, max mg/kg 24 24 24
Oxidation stability, max g/mg3 25 25 25
Polycylic Aromatic Hydrocarbon (PAH), max  % mass 11 11 11
Lubricity, corrected wear scar diameter (wsd 1,4) at 60 °C, max μm (microns) 460 460 460 460
Copper Strip corrosion for 3 hrs at 50 °C Rating Not worse than No. 1 Class I Class I Class I
a This limit is applicable prior to the addition of ignition improvers, if used. In case a value exceeding the limit is obtained on finished fuels in the market, ASTM D 4046 / ISO 13759 shall be used to establish the presence of a nitrate-containing compound. In such a case, the present limit for carbon residue cannot be applied. However, the use of ignition improver does not exempt the manufacturer from meeting this requirement prior to the addition of additives.
b For diesel process from Assam crude, either CN of 45 min or Cl of 43 min and density of 820–870 shall be applicable.

Non-road diesel

India currently does not have separate standards for commercial non-road diesel. Because most diesel for non-road vehicles and equipment is obtained from on-road vehicle fuel stations, consumers in the thirteen Bharat IV cities presumably use 50 ppm sulfur diesel to fuel construction equipment, and those in Bharat III areas likely use 350 ppm sulfur diesel. Agricultural tractors, most of which are in rural areas, also likely use 350 ppm sulfur diesel.

Gasoline

India’s current gasoline standards took effect in 2010. These standards required marked improvements from pre-2010 levels. Benzene limits were reduced from 3% in previously BS III cities and 5% elsewhere to 1% nationwide. The aromatic content limit, which was unregulated under BS II, stands at 42% under BS III norms and 35% under BS IV. Olefins, which were also unregulated under BS II, now stand at 21% and 18% for regular unleaded and premium unleaded, respectively, under BS III and BS IV regulations. Higher olefin content, along with higher Reid vapor pressure (RVP), tends to create more evaporative emissions, which leads to the formation of ozone (O3) and other toxins in the atmosphere. In 2010, sulfur content was lowered to 150 ppm nationwide and 50 ppm in Bharat IV compliant cities. Under BS II, the octane number was increased to 88 and 93 for regular and premium, respectively. It was further increased to 91 and 95 for regular and premium, respectively, under BS III and beyond. With the exception of reduced fuel sulfur content, the gasoline fuel quality mandated by BS VI is similar to that of BS IV fuel.

With respect to gasoline sulfur content, India presently lagged behind international best practices. At the start of 2013, 23 cities required no more than 50 ppm sulfur in gasoline, while up to 150 ppm sulfur was allowed in the rest of the country . In 2016, almost half of the country required 50 ppm gasoline. With the implementation of BS VI, India met the standards of international best practices to require 10 ppm sulfur gasoline.

Indian gasoline specification required meeting Bharat Stage II, III, & IV emission norms
Characteristics Unit Bharat Stage II Bharat Stage III Bharat Stage IV Bharat Stage VI
Implementation date 2001 (selected cities), 2005 (nationwide) 2005 (selected cities), 2010 (nationwide) 2010 (selected cities), 2017 (nationwide) 2020(nationwide)
Density 15°C Kg/m3 710–770 720–775 720–775 720–775
Research Octane Number (RON) min 88 91 91 91/95a
Anti-Knock Index (AKI) or Motor Octane Number (MON) min 84 81 81 81/85a
Sulphur, max ppm 500 150 50 10
Lead, max g/L 0.013 0.005 0.005 0.005
Benzene, max % volume 3 (metro), 5 (nationwide) 1.0 1.0 1.0
Aromatics, max  % volume 42 35 35
Olefin, max  % volume 21/18 21/18 21/18a
Oxygen Content, max  % mass 2.7 2.7 2.7
Reid Vapor Pressure (RVP) at 37.8ºC, max kPa 35–60 60 60 60
Fuel quality specification for regular/ premium gasoline

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