Improved in air quality during covid-19 period: a scenario for AOD and Ozone trends over major cities of India.Priyanshu Gupta1, Sunita Verma1, R Bhatla2, and Swagata Payra31. IESD, BHU Varanasi-221005 Uttar Pradesh, India2.Department of Geophysics, BHU.3. Department of Physics, Birla Institute of Technology Mesra, Jaipur Campus, Rajasthan India