Nationwide protests against record high petrol and diesel prices shut down businesses, government offices and schools in many parts of India on Monday, and in some places protesters blocked trains and roads and vandalised vehicles.
Gearing up for a general election less than nine months away and provincial polls expected in some states later this year, opposition parties banded together to organise their first protest action in a joint campaign to stir discontent with Prime Minister Narendra Modi's Hindu nationalist government.
Opposition Congress party activists marched, blocked roads and disrupted trains in the eastern Indian state of Odisha, while other opposition parties protested outside offices of oil marketing companies.
Congress leader Rahul Gandhi blamed the higher fuel prices and a falling rupee currency on the prime minister's policies.
"The rupee has never has been weaker in 70 years of independence," Gandhi said. "Farmers, labourers see no light at the end of the tunnel. Only 15-20 big industrialists are prospering."
Protesters burnt tyres and blocked traffic in the north eastern state of Assam. Several people were arrested in Assam and West Bengal, officials said.
Television footage showed protesters breaking car and bus windows in Patna, the capital of the northern state of Bihar.
Modi's Bharatiya Janata Party (BJP) accused its opponents of "unnecessarily politicising" high fuel prices and the weakening currency, which it blamed on external factors such as Turkey's economic crisis which affected emerging markets.
Ravi Shankar Prasad, the country's law minister, condemned the incidents of violence.
"The BJP strongly believes that despite some momentary difficulties, the people of India do not support this protest," he said in a televised address.
Taxes on petrol and diesel, which account for more than a third of retail fuel prices, are one of the biggest sources of income for the government, and an emotive issue for voters.
Past governments have usually lowered taxes when international oil prices shot up, but Modi's administration has made little concession so far.
Modi's popularity has come down in the past few months and his party is likely to face a tough challenge in three BJP-ruled states - Rajasthan, Madhya Pradesh and Chhattisgarh - expected to vote this year, and at the general election expected early next year.