Variation and correlation between ultraviolet index and tropospheric ozone during COVID-19 lockdown over megacities of India

“The entire UV-A radiation reaches to the earth’s surface as there is no incident of UV-A absorption by atmospheric ozone (Tan et al. 2018) while UV-C is wholly engrossed by ozone and oxygen in the upper and middle portion of the atmosphere (Chandra and Mcpeters 1994).”

“…megacities in India namely Delhi, Mumbai, Kolkata and Chennai have experienced the vibrant modifications in terms of the toxic air pollutants concentration including O3 during the lockdown phase (Central Pollution Control Board (CPCB) 2020; Sharma et al. 2020; Lau et al. 2020; Bera et al. 2020).”

“Atmospheric ozone has the potentiality to engross all types of UV-C rays and the captivation capacity of O3 has been augmented in terms of the reduction in wavelength of UV-B radiation (Fioletov et al. 2010).”

“…halting of industrial activities, vehicle movement, constructional works, burning of fuels markedly dwindle the concentration of lethal air pollutants like NO2, NO, CO and VOC in the atmosphere of these tremendously polluted cities (Central Pollution Control Board (CPCB) 2020; Sharma et al. 2020).”

“It must be remarkable that the global atmospheric quality as well as health of total environment has been restored at a certain limit because of restricted burnings of fuels, partly shut down of industrial production and transportation activities (Muhmmad et al. 2020).”

“…be stated that O3 is such an atmospheric constituent only which has the competency to captivate solar ultraviolet ray (UVR) within the range of 2000—3000 A and this phenomenon expressively guards the biota of the earth from life-threatening exposure to the noxious UV ray (Brasseur and Solomon1986).”

“The consumption of O3 is reduced due to curtail of NO emission and it improves the accumulation status of O3 in the troposphere (Andrade et al. 2017; Tobı́as et al. 2020).”

“In this context, the fact must be mentioned that the changing pattern of various meteorological elements like temperature, pressure, relative humidity, wind speed and direction can modify the creation and destruction process of surface O3 (Dueñas et al. 2002; Elminir2005; Satsangi et al. 2004).”

“…of its human-induced sources like yield of petroleum and natural gas (Gilman et al. 2013; Petron et al. 2012), transport activities (Russo et al. 2010), wood combustion (Kansal2009), industrial production (Gilman et al. 2009)during lockdown session (Central Pollution Control Board (CPCB) 2020).”

“The surface O3may exert detrimental impacts for natural vegetation, agricultural yields along with animal community and mankind (Bates 1994; Finlayson-Pitts and Pitts 1997; Hogsett et al. 1997; Wang et al. 2003; Garcia et al. 2005; Jerrett et al. 2009; Nishanth et al. 2014)and its presence exceeds…”

“…the lower atmosphere over Indian cities due to the closure of its human-induced sources like yield of petroleum and natural gas (Gilman et al. 2013; Petron et al. 2012), transport activities (Russo et al. 2010), wood combustion (Kansal2009), industrial production (Gilman et al. 2009)during…”

“…detrimental impacts for natural vegetation, agricultural yields along with animal community and mankind (Bates 1994; Finlayson-Pitts and Pitts 1997; Hogsett et al. 1997; Wang et al. 2003; Garcia et al. 2005; Jerrett et al. 2009; Nishanth et al. 2014)and its presence exceeds the permissible limit…”

“…accumulation of O3 had been recorded during the ending phase of autumn and entire winter season and this phenomenon is continued over the month of May in India (Varshney and Aggarwal1992; Lal et al. 2000; Naja and Lal 2002; Nair et al. 2002; Jain et al. 2005; Beig et al. 2007; Ghude et al. 2008).”

“…as secondary air pollutant and its origin is related with the composite photochemical procedures in the existence of volatile organic compounds (VOC), nitrogen oxides (NOx) and carbon monoxide (CO) which regulate the balance of surface O3(Fishman and Crutzen 1977, 1978; Garcia et al. 2005).”

“It must be stated that the alteration of NO2 level is remarkably prominent over Asian countries during COVID-19 lockdown while in India NO2 is sharply reduced by 70% amidst this global emergency (Gautam 2020).”

“The consumption of O3 is reduced due to curtail of NO emission and it improves the accumulation status of O3 in the troposphere (Andrade et al. 2017; Tobı́as et al. 2020).”

“…megacities in India namely Delhi, Mumbai, Kolkata and Chennai have experienced the vibrant modifications in terms of the toxic air pollutants concentration including O3 during the lockdown phase (Central Pollution Control Board (CPCB) 2020; Sharma et al. 2020; Lau et al. 2020; Bera et al. 2020).”

“…accumulation of O3 had been recorded during the ending phase of autumn and entire winter season and this phenomenon is continued over the month of May in India (Varshney and Aggarwal1992; Lal et al. 2000; Naja and Lal 2002; Nair et al. 2002; Jain et al. 2005; Beig et al. 2007; Ghude et al. 2008).”

“…accumulation of O3 had been recorded during the ending phase of autumn and entire winter season and this phenomenon is continued over the month of May in India (Varshney and Aggarwal1992; Lal et al. 2000; Naja and Lal 2002; Nair et al. 2002; Jain et al. 2005; Beig et al. 2007; Ghude et al. 2008).”

“In this context, the fact must be mentioned that the changing pattern of various meteorological elements like temperature, pressure, relative humidity, wind speed and direction can modify the creation and destruction process of surface O3 (Dueñas et al. 2002; Elminir2005; Satsangi et al. 2004).”

“…as secondary air pollutant and its origin is related with the composite photochemical procedures in the existence of volatile organic compounds (VOC), nitrogen oxides (NOx) and carbon monoxide (CO) which regulate the balance of surface O3(Fishman and Crutzen 1977, 1978; Garcia et al. 2005).”

“…also curtailed in the lower atmosphere over Indian cities due to the closure of its human-induced sources like yield of petroleum and natural gas (Gilman et al. 2013; Petron et al. 2012), transport activities (Russo et al. 2010), wood combustion (Kansal2009), industrial production (Gilman et al.…”

“…to the closure of its human-induced sources like yield of petroleum and natural gas (Gilman et al. 2013; Petron et al. 2012), transport activities (Russo et al. 2010), wood combustion (Kansal2009), industrial production (Gilman et al. 2009)during lockdown session (Central Pollution Control Board…”

“…accumulation of O3 had been recorded during the ending phase of autumn and entire winter season and this phenomenon is continued over the month of May in India (Varshney and Aggarwal1992; Lal et al. 2000; Naja and Lal 2002; Nair et al. 2002; Jain et al. 2005; Beig et al. 2007; Ghude et al. 2008).”

“…accumulation of O3 had been recorded during the ending phase of autumn and entire winter season and this phenomenon is continued over the month of May in India (Varshney and Aggarwal1992; Lal et al. 2000; Naja and Lal 2002; Nair et al. 2002; Jain et al. 2005; Beig et al. 2007; Ghude et al. 2008).”

“…of its human-induced sources like yield of petroleum and natural gas (Gilman et al. 2013; Petron et al. 2012), transport activities (Russo et al. 2010), wood combustion (Kansal2009), industrial production (Gilman et al. 2009)during lockdown session (Central Pollution Control Board (CPCB) 2020).”

“Different anthropogenic activities like burning of fossil fuel, heating activities in industrial furnace, diesel combustion expand the accumulation of air pollutants like nitrogen oxides (NOx) over extremely polluted cities (Barck et al. 2005; Carslaw2005; Carslaw and Beevers 2004a, b).”

“…animal community and mankind (Bates 1994; Finlayson-Pitts and Pitts 1997; Hogsett et al. 1997; Wang et al. 2003; Garcia et al. 2005; Jerrett et al. 2009; Nishanth et al. 2014)and its presence exceeds the permissible limit (200 lg/m3 or 0.2 mg/m3 or 0.1 ppm) in the troposphere (Bera et al. 2020).”

“During the lockdown period, the halting of transport movement, industrial activities and power generation ensure the cleanliness of atmosphere, refurbishment of ozone layer and purification of the total environment (Chakraborty and Maity 2020; Chakraborty et al. 2021a, b).”

“During the lockdown period, the halting of transport movement, industrial activities and power generation ensure the cleanliness of atmosphere, refurbishment of ozone layer and purification of the total environment (Chakraborty and Maity 2020; Chakraborty et al. 2021a, b).”

“…accumulation of O3 had been recorded during the ending phase of autumn and entire winter season and this phenomenon is continued over the month of May in India (Varshney and Aggarwal1992; Lal et al. 2000; Naja and Lal 2002; Nair et al. 2002; Jain et al. 2005; Beig et al. 2007; Ghude et al. 2008).”

“In this context, the fact must be mentioned that the changing pattern of various meteorological elements like temperature, pressure, relative humidity, wind speed and direction can modify the creation and destruction process of surface O3 (Dueñas et al. 2002; Elminir2005; Satsangi et al. 2004).”

“…natural vegetation, agricultural yields along with animal community and mankind (Bates 1994; Finlayson-Pitts and Pitts 1997; Hogsett et al. 1997; Wang et al. 2003; Garcia et al. 2005; Jerrett et al. 2009; Nishanth et al. 2014)and its presence exceeds the permissible limit (200 lg/m3 or 0.2…”

“…accumulation of O3 had been recorded during the ending phase of autumn and entire winter season and this phenomenon is continued over the month of May in India (Varshney and Aggarwal1992; Lal et al. 2000; Naja and Lal 2002; Nair et al. 2002; Jain et al. 2005; Beig et al. 2007; Ghude et al. 2008).”

“The existence of surface O3 is dependent on the share of production and annihilation of NO as O3has the competency to speedily react with nitric oxide (Vellingiri et al. 2015).”

“…of social isolation is highly required to prevent the deadly impacts of this noxious infectious disease and worldwide almost all governments have imposed this social distancing norms to combat the disastrous outbreak of COVID-19 (Huang et al. 2020a, b; Zhang et al. 2020; Bera et al. 2021).”

“The relevant statistical applications are used to deduce the proper inter-relation and consistency level among the selected variables (Bera et al. 2019).”

“The entire UV-A radiation reaches to the earth’s surface as there is no incident of UV-A absorption by atmospheric ozone (Tan et al. 2018) while UV-C is wholly engrossed by ozone and oxygen in the upper and middle portion of the atmosphere (Chandra and Mcpeters 1994).”

“This harmful radiation can weaken the human immunity system and it is severely injurious for eyes and skin (Meves et al. 2003).”

“…of social isolation is highly required to prevent the deadly impacts of this noxious infectious disease and worldwide almost all governments have imposed this social distancing norms to combat the disastrous outbreak of COVID-19 (Huang et al. 2020a, b; Zhang et al. 2020; Bera et al. 2021).”

“In addition to the strength of the stratospheric polar vortex, the El Niño Southern Oscillation and the Indian Ocean Dipole also affect weather conditions in Australia [172].”

“Bera et al. (2021) recorded an increase of ozone by 4.14% in New Delhi, 3.58% in Mumbai, 2.28% in Kolkata, and 1.26% in Chennai during lockdown (April 2020) compared to prelockdown (April 2019) year.”

“During the lockdown period, Bera et al. [6] observed the UV index which is related to the tropospheric ozone over Kolkata, Delhi, Mumbai, and Chennai—four megacities of India.”