An Indian oil tanker, detained by Iran for nearly a month, finally arrived at Visakhapatnam port in the southern state of Andhra Pradesh on Wednesday, sources said. \"MT Desh Shanti docked at Visakhapatnam port at 5.35 a.m. It was released on September 6 following intense negotiations between India and Iran after Iranian Revolutionary Guards Corps detained the vessel on August 12 in the Persian Gulf,\" the sources said. India had lodged a strong protest with Iran about the detention of the ship which was carrying 140,000 tonnes of crude oil from Iraq to Visakhapatnam. Tehran said that the vessel was detained on environmental pollution concerns.