New Delhi: Skipping Bharat Stage (BS) V emission norms, equivalent to Euro V norms, and moving directly to BS VI norms for vehicles could lead to safety and quality problems such as self-acceleration and engine damage, Bosch Ltd, India’s largest manufacturer of fuel injection systems and engine technologies, told the government.

Bosch, in a letter dated 5 June, said that in order to change from BS IV to BS V, it needs as much as four-and-a-half years of lead time for design, application and validation of new engine technologies, and similar time to graduate to BS V1.

Mint has reviewed a copy of the letter.

The letter was in reference to a high-level meeting that the ministry of heavy industries (MHI) held on 3 June to discuss whether the auto industry could skip BS V and graduate directly to BS VI, from the current BS IV emission norms.

The Indian government is under international pressure to reduce pollution levels across the country.

According to a 2 May Times of India report, environment secretary Ashok Lavasa has written to the Prime Minister’s Office to take a call on skipping BS V norms.

In the letter, Bosch said the development and validation of emission technologies have three phases—design and application take one year each, while validation needs two to two-and-a-half years.

“If these phases are not followed, it can lead to severe safety and quality problems in the field, like self-acceleration, engine damage, etc.," Friedrich Boecking, regional president (diesel systems), Bosch, said in the letter addressed to the MHI secretary.

According to an industry expert, who spoke on condition of anonymity, while there is not much difference in the quality of BS V and BS VI fuel—with the sulphur content nearly the same—moving to BS VI directly requires a significant technology upgrade and an investment between 40,000 crore and 60,000 crore by the auto industry.

As per the original timeline in the Auto Fuel Policy, BS IV is to be adopted across the country by 2017, BS V by 2020 and BS VI by 2024. Many western countries have already graduated to Euro VI, the equivalent to BS VI.

The deadlines are set to be advanced by a year.

In an interview over the phone, Boecking said a “very good" application and validation tested across seasons (winter, summer and monsoon) is required. If not done properly, the chances of a car catching fire are high, he warned.

“We need more time for BS VI. One should understand that the conditions in India are very different from Europe. It’s better to take a step-by-step approach," he said.

Currently, India has BS IV emission norms for vehicles. These were introduced in April 2010 and all passenger vehicles manufactured since then have been compliant with these emission norms. However, BS IV fuel is not available across the country because refiners such as Indian Oil Corp. Ltd and Bharat Petroleum Corp. Ltd, among others, have not managed to produce this fuel in large quantities.

BS IV petrol and diesel contain less sulphur, a major air pollutant, than BS III-compliant fuels, and are critical to lowering pollution and improving air quality. Moving from BS III norms to BS V itself reduces particulate matter (PM) emission further by up to 90%, according to the Society of Indian Automobile Manufacturers, or Siam.

“A further upgradation to BS VI only offers an incremental 0-10% advantage in PM emissions," Vikram Kirloskar, president, Siam, said on Monday.

Queries to the ministry of petroleum remained unanswered at the time of going to press.