**1. Introduction**

India reported its first COVID-19 case on January 30th, 2020 which was about the same day when World Health Organization (WHO) declared this outbreak "a public health emergency of international concern" [1, 2]. Today, when India is reporting ~100,000 cases every day, an extreme load on healthcare system is proving to be a challenging situation for the middle-income nation [3]. World Health Organization (WHO) accounted first severe acute respiratory syndrome coronavirus (SARS-CoV) from 2002 to 2003, which spread through 26 countries across the world and was considered 'the first serious emergent disease of 21st century' [4]. The Coronavirus disease (COVID-19) spread in 2019–2020 is caused by a novel coronavirus designated as SARS-CoV-2 [5]. Coronaviruses belong to Coronaviridae family of the order Nidovirales whose members are large and enveloped containing a single-stranded (+) RNA as genetic material, these are considered the largest known RNA viruses with genome size of 25 to 32 kb and virions of 118–140 nm in diameter [6]. Within the family Coronaviridae there are

two sub-families- Coronavirinae and Torovirinae further divided into six genera out of which members of the genus Betacoronavirus infects mostly mammals and genus Deltacoronavirus infect mammalian as well as avian hosts [7]. The COVID-19 causing SARS-CoV-2 belongs to genus Betacoronavirus [8].

As the surge in the number of cases started to be reported all across the world, major disparities on the basis of ethnicity, gender and populations were also noticed in different regions. The advancing age, and pre-existing medical conditions like diabetes, high blood pressure (BP), renal-associated diseases etc. increase the vulnerability of a person towards the severity in consequences of the disease [9, 10]. However, a surprising observation emanating from the pandemic is the rate of hospitalization of younger, ostensibly healthy individuals; which reflects that differences in the vulnerability of individuals to infection in the spectrum of COVID-19 symptoms remain to be understood [11]. This review will focus upon some of the studies leading to understanding the genomics of Indian populations and their vulnerabilities towards the SARS-CoV-2 infection, the studies relating to the mitochondrial impacts of the SARS-CoV-2 infection, molecular mechanisms through which ACE2 expression affects the viral pathogenesis and about two potential drug candidates of COVID-19.

This chapter provides an account on some of the major contributions towards the understanding the COVID-19 disease by Indian scientists and researchers.
