The National Company Law Appellate Tribunal (NCLAT) restored Cyrus Mistry as Tata Sons ' executive chairman today, three years after his sacking at a board meeting after which Ratan Tata took office as interim chairman. The tribunal said the decision would apply only after four weeks – the time allowed to the Tatas to challenge the order before the Supreme Court. The court held the transformation of the company from public to private as illegal and also rejected Natarajan Chandrasekaran's role as executive chairman of the conglomerate of salt-to-software.