Which is the largest car manufacturer in india?
by sheer volumes of sales it has to be the Maruti Suzuki. it has a a 40% share of the market. it sells a million cars every year which the next top 4(hyundai, tata motors, mahindra and toyota) put together.
its manufacturing capacity is 2 million of the remaining it uses for export purpose. but maruti suzuki's main market has always been the domestic market(India) as it does not export more cars compared to hyundai which is a leading exporter and also enjoys a good subsidy from the government. this subsidy is used to consolidate its market share in the domestic market.
so the largest car manufacturer by sales and capacity is hands down maruti suzuki.
This video gives a rough idea