India has extended its futures trading ban to four more food commodities despite warnings, including from the government-appointed market regulator, that such measures will do nothing to quell inflation.

The regulator, the forward markets commission, acting under instruction from the Congress party-led coalition government, suspended futures trading on Thursday in potatoes, soy oil, rubber and chickpeas for at least four months. Last year it banned futures trading in wheat, rice and two types of dhal.