Dr B. R. Ambedkar established the All India Depressed Classes Association (and held the All India Depressed Classes Congress at Nagpur) in:

Dr B. R. Ambedkar established the All India Depressed Classes Association, and the first session of the All India Depressed Classes Congress was held at Nagpur in August 1930, under his presidency.

Background:

• In the 1920s, Ambedkar had become the leading spokesman of the depressed classes (the communities then treated as "untouchables").
• The Simon Commission (1928) and the coming constitutional reforms made the question of the political representation of the depressed classes very important.

The Nagpur Congress (1930):

• In August 1930, the All India Depressed Classes Congress met at Nagpur, with Ambedkar as President.
• In his speech, Ambedkar declared that the depressed classes wanted self-government for India, but they also wanted to have political power for themselves in the new India.
• He criticised both the British government, which had done little to improve their condition, and the caste Hindus, who practised untouchability.
• He demanded adequate representation for the depressed classes in the legislatures and in the public services.

The Round Table Conferences:

• Ambedkar represented the depressed classes at the conferences held in London on Indian constitutional reforms.
• He demanded separate electorates for them.

Ambedkar's other organisations:

• He founded the Independent Labour Party in 1936, to represent the interests of workers and the depressed classes.
• In 1942, he founded the All India Scheduled Castes Federation.

Other movements of the time:

In the late 1920s and early 1930s, Ambedkar led movements for the right of the depressed classes to use public water sources and to enter temples.

Why not the other options?

• ✗1920 was the year Ambedkar started "Mooknayak".
• ✗1936 and 1942 were the years of his later political parties.