GUWAHATI, March 16: Assam PWD Minister Ajanta Neog today informed the State Assembly that the Centre had already approved Rs 112 crore for the improvement of the 110-km National Highway-44 (Assam portion), considered the lifeline of the Barak Valley, and that the tendering process was under way in New Delhi. She said the single-lane highway would be made a two-lane one by 2012/13.