By Chris Thomas and Aditya Kalra BENGALURU (Reuters) – Hindenburg Research said on Wednesday it held short positions in Adani Group, accusing the Indian conglomerate of improper extensive use of entities set up in offshore tax havens and expressing concern about high debt levels. The group, which is led by Gautam Adani, the world’s third richest person according to Forbes, dismissed the U.S. short-seller’s claims as baseless, saying it was timed to damage its reputation ahead of a large share offering. The group’s flagship firm, Adani Enterprises, will on Jan. 27 launch the country’s biggest p…