Trade unions originated in India in response to the harsh conditions faced by workers after the introduction of industrialization in the 1850s. The first trade union was formed in 1875 led by Sorabjee Shahpurjee Bengali. From 1875 to 1918, several unions were established to advocate for workers' rights and better working conditions. After World War 1, larger national unions were formed like the All India Trade Union Congress in 1920. The period from 1924 to 1933 saw the emergence of left-wing unions and greater legal recognition of trade unions through the Trade Union Act of 1926.