KATHMANDU: Thousands of Indian farmers protesting against the controversial agricultural reforms entered the Indian capital to participate in the massive rally, coinciding with Republic Day of the biggest democracy in the world, on Tuesday.

A clash ensued with between the protesting farmers and police as the latter fired tear gas shells to restrain the convoy of tractors that breached the barricades and attempted to enter the inner parts of the city.

Indian farmers have been protesting against the government for almost two months, posing one of the biggest challenges to Prime Minister Narendra Modi since he came to power in 2014.

"Modi will hear us now, he will have to hear us now," said Sukhdev Singh, 55 to Reuters, a farmer from the northern breadbasket state of Punjab, as he marched past the barricades.

Agriculture employs about half of India's population of 1.3 billion, and unrest among an estimated 150 million landowning farmers worries the government.

"They could have chosen any other day instead of January 26 but they have announced now," Agriculture Minister Narendra Singh Tomar told media on Monday.

Nine rounds of talks with farmers' unions have failed to end the protests, as farm leaders rejected the government's offer to delay the laws for 18 months, making a push for repeal instead.