P. Thankappan Nair writes, “The six square miles within the Maratha Ditch (the original core of Calcutta) thus came to have the world’s highest density of population in that age. It was a heterogeneous population, sinking differences of caste, creed and colour under the sheer compulsion to interact and survive together. The compulsion has grown stronger ever since, as has the spirit it fostered. Hence Calcutta did not disintegrate when the capital was shifted to New Delhi in 1912. It has kept growing and living by the ever-renewed confidence and vitality of its inherent human forces.”