1 May, celebrated in many countries as a traditional springtime festival or as an international day honouring workers.

International Workers' Day, also known as Labour Day in some places, is a celebration of labourers and the working classes that is promoted by the international labour movement, socialists, communists and anarchists and occurs every year on May Day, 1 May, an ancient European spring holiday. The date was chosen for International Workers' Day by the Second International, a pan-national organization of socialist and communist political parties, to commemorate the Haymarket affair, which occurred in Chicago on 4 May 1886. The 1904 International Socialist Conference in Amsterdam, the Sixth Conference of the Second International, called on "all Social Democratic Party organisations and trade unions of all countries to demonstrate energetically on the First of May for the legal establishment of the 8-hour day, for the class demands of the proletariat, and for universal peace."
Being a traditional European spring celebration, May Day is a national public holiday in many countries, but in only some of those countries is it celebrated specifically as "Labour Day" or "International Workers' Day". Some countries celebrate a Labour Day on other dates significant to them, such as the United States, which celebrates Labor Day on the first Monday of September.

India

Triumph of Labour at the Marina Beach in Chennai

In India, Labour Day is a public holiday held on every 1 May. It is celebrated as Antarrashtriya Shramik Diwas. The holiday is tied to labour movements for communist and socialist political parties. Labour Day is known as "Kamgar Din" in Hindi, "Kamgar Divas" in Marathi and "Uzhaipalar dhinam" in Tamil. In North India, Labour Day is mostly not given its previous importance as a holiday now.

The first May Day celebration in India was organised in Madras (now Chennai) by the Labour Kisan Party of Hindustan on 1 May 1923.This was also the first time the red flag was used in India.The party leader Singaravelu Chettiar made arrangements to celebrate May Day in two places in 1923. One meeting was held at the beach opposite to the Madras High Court; the other meeting was held at the Triplicane beach. The Hindu newspaper, published from Madras reported,

The Labour Kisan party has introduced May Day celebrations in Madras. Comrade Singaravelar presided over the meeting. A resolution was passed stating that the government should declare May Day as a holiday. The president of the party explained the non-violent principles of the party. There was a request for financial aid. It was emphasised that workers of the world must unite to achieve independence.

1 May is also celebrated as "Maharashtra Day" and "Gujarat Day" to mark the date in 1960, when the two western states attained statehood after the erstwhile Bombay State was divided on linguistic lines. Maharashtra Day is held at Shivaji Park in central Mumbai. Schools and offices in Maharashtra remain closed on 1 May. A similar parade is held to celebrate Gujarat Day in Gandhinagar.