Noel Tata has challenged the validity of N Chandrasekaran's five-year reappointment as Tata Sons chairman, citing procedural lapses and the absence of the resolution from the meeting agenda. Tata Trusts chairman Noel Tata on Monday challenged the resolution to reappoint N Chandrasekaran as the chairman of Tata Sons, which was passed at the September 17 board meeting of the holding company of the country's largest conglomerate.