1 Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India. Electronic address: inderpgi@outlook.com.
2 Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
3 Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India; Department of Pulmonary and Critical Care Medicine, Postgraduate Institute of Medical Sciences, University of Health Sciences, Rohtak, Haryana, India.