Khulna is the main city in Khulna Division in Bangladesh. On the bank of the Rupsha (and Bhairav) river, it is known as the industrial city and located in the southern part of Bangladesh. A large part of the Sundarbans, a UNESCO world heritage is located in Khulna. It has many Jute mills, the only newsprint mill and hardboard mill of Bangladesh, the only state-owned match factory (Dada match, later Dhaka match), Oxygen company (BOL), Shipyard. Khulna is the 4th largest city in Bangladesh after Dhaka, Chittagong, and Comilla. It is a quiet, calm city inhabited by 1.5 million people.