How will the new Maruti Suzuki car GST rate affect India’s fuel consumption and oil imports?

I don’t think impact will be very large. Even if 5 lakh more cars are sold, compared to total fuel consumption of the country, this increase is very small. Industries and trucks consume far more oil than cars.

If more people buy cars because of GST cut, then obviously fuel demand will go up. India already imports a lot of oil. With more Maruti cars running on petrol, consumption will rise further. This may affect trade deficit also, because we import oil in huge quantities. So while GST cut helps economy in one way, it may also increase oil bill.