New Delhi, Oct. 17 -- India's top carmakers have missed the deadline to submit feedback on a fresh set of emission norms proposed by the government. Industry comments were sought by 16 October (Thursday), but automobile lobby Society of Indian Automobile Manufacturers (Siam) is yet to send in a consolidated response.

The silence reflects frustration within the industry over proposed relaxations for small cars, even as they huddled to put together a joint response, according to two executives aware of the matter who spoke on condition of anonymity as internal industry discussions were still ongoing.

While earlier debates on Cafe 3 norms saw a tussle between carmakers that have invested in larger SUVs versus those that invested in smaller...