Here are 10 developments in this big story:
Union Home minister Amit Shah held a high-level meeting on Tuesday evening where a decision was taken to deploy additional paramilitary forces in Delhi. Punjab and Haryana have been placed under high alert. Internet has been suspended in parts of the National Capital Region -- including Delhi and parts of Uttar Pradesh and Haryana.
The Delhi Police had allowed a rally with a fixed route and time. But the Kisan Mazdoor Sangharsh Committee refused to stick to the route. By 8 am, thousands entered the national capital on foot. Dramatic visuals showed farmers breaching barriers at the Singhu border, the epicentre of protests against the farm laws that started on November 26.
Violence broke out at central Delhi's ITO, where the police headquarters is located. A farmer died there as a tractor on way to the Old City overturned, the police said. A bus was vandalized in nearby Akshardham, where the police clashed with protesters. The other flashpoint was Nangloi, where the police used teargas shells. The Delhi Metro Rail Corporation shut the gates at several metro stations.
Visuals from the Red Fort showed farmers hoisting a sacred flag of Sikhs at a second flagpole. Repeated attempts were made to hoist flags on the fort's domes as well. Thousands of others, waving the national flag, stood at the huge gates of the fort. The police have managed to push out protesters from inside the fort. But many are still thronging the Ramlila grounds outside the fort.
"We came here to deliver a message to the Modi government, our job is done. We will go back now," one of the farmers told NDTV at the Red Fort. "We managed to reach the fort even though they tried to stop us. We will not stop till we reach our goal -- the repeal of the three farm laws," another farmer said.
The police have filed 15 cases so far. Eight buses and 17 private vehicles were vandalised, the police said. Despite having fixed routes, "farmers drove tractors off the routes and before the fixed time, leading to vandalism in which many police personnel were injured," said Delhi Police chief SN Shrivastava. Overall, 86 police personnel have been injured in the violence.
A key pan-India farmers' group, Samyukt Kisan Morcha, called off the tractor rally, asking participants to return to the protest sites outside Delhi borders. The group also said anti-social elements had "infiltrated the otherwise peaceful movement". "The long struggle for more than 6 months now, and more than 60 days of protest at Delhi borders also seemed to have led to this situation," it added.
Farmers were given police permission to hold the rally on the periphery of the city after a court battle. The rally -- to be held over 60-odd-km stretches near the Singhu, Tikri and Ghazipur borders -- was expected to enter the city only after the traditional Republic Day parade ended around 11.30 am.
The Centre had opposed the rally in the Supreme Court, contending that its timing will make it "an embarrassment to the nation". But the court, which earlier upheld the farmers' right to hold peaceful protests, handed over the matter to the Delhi Police.
No breakthrough in the deadlock over the farm laws has been possible despite 11 rounds of talks between the farmers and the government. The farmers turned down the Centre's last offer to put the laws on hold for 18 months while a special committee conducts negotiations.