Fix grammatical mistakes in this sentence: He worked as the Chairman & MD of NBCC (National Building Construction Company), a Navaratna Central Public Sector Company from 3rd April 2001 to 31st August 2010 and as Chairman and MD of NTPC (National Thermal Power Company) a Maharatna Central Public Sector Company from 1st September 2010 till 31st August 2015.
He worked as the Chairman & MD of NBCC (National Building Construction Corporation), a Navaratna Central Public Sector Company from 3rd April 2001 to 31st August 2010 and as Chairman and MD of NTPC (National Thermal Power Corporation) a Maharatna Central Public Sector Company from 1st September 2010 till 31st August 2015.