UPDATE 1-Cairn Energy sues Air India to enforce $1.2 bln arbitration award - court filing

(Adds background and details on legal tussle) MUMBAI/NEW YORK, May 15 (Reuters) - Cairn Energy has sued India's flagship carrier Air India to enforce a $1.2 billion arbitration award that it won in a tax dispute against India, according to a U.S. District Court filing reviewed by Reuters. The move...