China is raising its sales tax on big cars to as high as 40 percent, and drastically cutting taxes on small cars, in its latest attempt to combat emissions that contribute to heavy blankets of smog over most of its cities.

The tax on passenger vehicles with engines bigger than 4 liters will be doubled to 40 percent from 20 percent, effective Sept. 1, the Finance Ministry said in a statement on its Web site. Those buying vehicles with engines sized from 2 liters up to 4 liters will have to pay a 25 percent tax, up from the current 15 percent, it said.

Read more about the China gas tax here.