The new National Green Tribunal (NGT) order banning registration of diesel cars until the next hearing is causing unrest in the automobile industry, as insiders believe 12,000 diesel cars could have been sold till 6 January.

The order states that no new diesel cars be registered and cars older than 10 years be banned.

"It's not correct to blame only diesel cars for environmental concerns. The decision should be holistic. This is a sudden order which has been made without consulting us. Delhi's pollution is largely due to the city's climatic conditions and very little due to diesel engines," Vishnu Mathur, director general of the Society of Indian Automobile Manufacturers (SIAM) told DNA.

The NGT order comes after the first shocker to the automobile industry when the Delhi government issued a rule that only odd and even-numbered cars would be allowed on the streets on alternate days.

Mahindra & Mahindra (M&M), Tata Motors, Hyundai, Toyota, Renault and other major diesel car-manufacturers would be the worst hit by the new order by the tribunal.

"This is injustice for the entire sector. What is the logic of banning vehicles compliant with BS-IV norms, which were made mandatory in October in certain states?" said Pawan Goenka, Executive Director of M&M.

"This sudden judicial directive has created concerns among buyers towards delivery of their vehicles for which payment has already made. The government also needs to look at the diesel inventory at dealerships, which raise concerns towards the cost of inventory and its future," DNA quoted Rakesh Srivasatva, Senior Vice-President for sales and marketing at Hyundai Motor India, as saying.

"We reserve our comments as the decision is pending with the government and the courts. However, the government should seriously consider createing a robust roadmap for the automobile industry. The industry has already made plans to invest in diesel technology as per BS-V norms to be implemented by 2019, and such decisions can negatively impact the sector," he added

Quoting the IIT-K study which revealed that only 2.5% of the pollution in Delhi is caused by vehicles, SIAM has said: "The air quality in the city deteriorates every September and gets better in January. This is the normal climate cycle of Delhi for last 10 years."

M&M's Goenka said: "BS-IV vehicles are contributing only 0.5% to the total particulate matter (PM) 2.5 load in Delhi. In the last 15 years, PM has come down 82% and mono-nitrogen oxides (NoX) 51%. PM will come down another 80% from the current levels by the time BS-V is implemented."

The Transport Ministry notification mandates that cars made on or after April 1, 2017, will follow BS-IV norms.