Who coached the "queen of Indian track and field"?
O. M. Nambiar: O. M. Nambiar (born 1932) is an Indian athletics coach who was awarded Dronacharya award in 1985. O. M. Nambiar:  He coached the well known Indian athlete P. T. Usha. P. T. Usha: Pilavullakandi Thekkeparambil Usha (born 27 June 1964), popularly known as P. T. Usha, is a retired Indian track and field athlete. P. T. Usha:  She is often called the "queen of Indian track and field".
O. M. Nambiar