The relevant information is: Kolkata was the capital of the British Indian empire until 1911 when the capital was relocated to Delhi.
This justifies what answer for what question? Q & A:
Passage: Kolkata, formerly known as Calcutta in English, is the capital of the Indian state of West Bengal and is located in eastern India on the east bank of the River Hooghly. The city was a colonial city developed by the British East India Company and then by the British Empire. Kolkata was the capital of the British Indian empire until 1911 when the capital was relocated to Delhi. Kolkata grew rapidly in the 19th century to become the second city of the British Empire. This was accompanied by the development of a culture that fused European philosophies with Indian tradition.

Question: Based on this passage, calcutta was capital of british till which year?
1911