A prolonged strike could cause major problems
Prices of fruit and vegetables have started to rise in some Indian cities as a nationwide strike by lorry drivers continued for a third day.
Truck operators want cheaper diesel and exemption from road tolls. Talks with the government have broken down. Most freight in India goes by road.
A prolonged strike will further push up costs of essential goods, analysts say.
Meanwhile, more than 45,000 public sector employees in the oil industry are also threatening industrial action.
They are demanding higher wages. The petroleum ministry has responded by saying it will take action against them if they go on strike.
'Hike in prices'
Reports say up to six million lorries remain off India's roads.
Vegetable traders in the capital, Delhi, and Mumbai (Bombay) say the action is beginning to be felt - although there are no reports of shortages of essential goods.
"It has led to a hike in the prices of vegetables," Ashok Kumar, a vegetable trader at Delhi's biggest vegetable market, Azadpur, told the Reuters news agency.
Fruit and vegetable vendors in Mumbai also told the BBC that prices had begun to go up.
On Tuesday, India's Minister for Surface Transport and Shipping, TR Baalu, called on transporters to call off their strike.
"I appeal to them to resume their duties immediately and come forward for a fruitful negotiation with us," he told reporters.
The government threatened to revoke the truckers' licences after talks with them broke down over the weekend.
Lorry drivers say they have been hit hard by high fuel prices and the economic slowdown.
"We are on an indefinite strike until our demands are met," Charan Singh Lohara, president of the All India Motor Transport Congress (AIMTC), said.
"The government is giving concessions and bailout packages to so many industries. Why not us when we are struggling to repay loans with high fuel prices, high prices of tyres and numerous taxes?"
Indian consumers are yet to recover from last year's high inflation figures which reached double digits a few months ago, before coming down in the past few weeks.