1 Department of Community Medicine, University College of Medical Sciences and GTB Hospital, and *Department of Neonatology, Maulana Azad Medical College and associated Lok Nayak Hospital; New Delhi, India. Correspondence to: Dr. Amir Maroof Khan, Associate Professor, Department of Community Medicine, University College of Medical Sciences and GTB Hospital, Dilshad Garden, Delhi, India. khanamirmaroof@yahoo.com.