High Quality Content by WIKIPEDIA articles! Karatoya River (also spelt Korotoa), a small stream in Rajshahi Division of Bangladesh, was once a large and sacred river. A channel of it presently flows by the ancient ruins of Mahasthangarh (or Pundranagara, ancient capital of Pundravardhana) in Bogra District. The Karatoya mahatmya bears testimony to its past greatness. In the Mahabharata it is mentioned that a visit to the Karatoya after three days fast produces the same merit as an aswamedha (horse killing) sacrifice. Another ancient city, Sravasti, may have been located on the banks of the Karatoya, north of Mahasthangarh. However, there is a controversy about the possible location of Sravasti.