Calcutta

 was a city in India.

The Fifth Doctor materialised the TARDIS in Calcutta on 31 December 1926 with the intention of taking his companions Nyssa, Tegan Jovanka and Turlough to the second Unofficial Test match between All India and Marylebone Cricket Club (MCC), which was played in the city on that day. The MCC won the match by four wickets. The Doctor considered it to be one of the best cricket matches of all time. (AUDIO: The Emerald Tiger)

Ian Gilmore was once posted in Calcutta. (AUDIO: The Fifth Citadel)

The Tenth Doctor and Donna Noble travelled to Calcutta in 1947. According to the Doctor, it was at the heart of the strife caused by the British Raj's failure to respond to a famine in the subcontinent in 1946. When the British didn't act to safeguard the people, Indians revolted and demanded independence. However, since the people of India were of many different faiths, the country was immediately plunged into a kind of religious civil war. Calcutta was at the front lines of this faith-based struggle — something which the Tenth Doctor and Donna observed at close range. (PROSE: Ghosts of India)

Behind the scenes
The details given in Ghosts of India are not entirely historically accurate. The independence-triggering famine was not in 1946, but. However, the implication of inherent in Ghosts of India, and Calcutta's tumultuous place in it, is more or less "correct" when compared to real life events in 1947.