Indian farmers who have been blockading New Delhi on Tuesday launched a one-day, nationwide general strike to push their demands for the government to repeal reform laws opening up trade in agricultural produce. Tens of thousands of farmers have been camped on the outskirts of the capital since November 27 in protest at the laws in what has become one of the biggest challenges to the Hindu nationalist government since it won a second landslide election in 2019. Farmers have vowed to block major roads and rail lines across the country for several hours and have been given support by railway workers, truck drivers, teachers and other unions. Authorities have put thousands of extra police on the streets in Delhi and boosted security in the rest of the country in a bid to head off any trouble. Five rounds of talks have failed to narrow differences between farmers and ministers. The growing numbers of farmers and their supporters camped outside the capital say they will not go home until the laws are repealed. The laws will allow farmers to sell their produce on the open market — including to supermarket chains — instead of being forced to sell through state-run organisations that guarantee a minimum price. The farmers say the industry will be taken over by major firms who will force prices down. The government insists the changes are necessary to give agriculture — still the backbone of the Indian economy — a long-term future. The protests have already caused price rises for fruit and vegetables in Delhi because supplies are restricted. Rakesh Tikait, a protest leader, said that people should not travel during the shutdown and all stores should close. Balbir Singh Rajewal, another leader, said: “We want nothing less than a withdrawal of the new farm laws.” The main opposition Congress party and about 15 other political groupings are backing the protest but the government has accused them of opportunism, rejecting measures that they had called for when in power. The farmers are strongest in the north of the country, but even the government in the southern state of Karnataka suspended online school lessons for the day to show support. Top athletes including wrestler Kartar Singh, who won gold medals at the Asian Games in 1978 and 1986, said they would return national awards in protest at the laws. Singh alongside hockey player Gurmail Singh — gold medallist at the 1980 Moscow Olympics — and former women’s hockey captain Rajbir Kaur tried to march on the presidential palace on Monday to hand back awards but were stopped by police. A new round of talks on the disputed laws are to be held on Wednesday.