In depth
The First Amendment was the first change to the Constitution, enacted a little over a year after it came into force. It dealt with three areas at once: agrarian reform laws, limits on the rights in Article 19, and special provisions for backward classes.
On land, state governments had passed laws abolishing zamindari. Some were challenged in High Courts as violating fundamental rights. The Patna High Court struck down the Bihar Land Reforms Act, 1950 on Article 14 grounds. The Supreme Court majority later upheld the Act with two sections excluded. Article 31B, with a schedule of validated laws, protected such enactments, and the schedule was later expanded by further amendments.
The sources reviewed give the legal structure but not a reliable national figure for the area or the number of tenants affected by zamindari abolition, so the effect on land distribution is not quantified here. Evaluations of land reform generally describe wide variation across states.