Introduction

Abstract

Being a living community on the planet earth, utilization of natural resources is quite obvious by humans. However, the overexploitation of these resources during past two decades has resulted in major environmental problems. Increasing human population and energy demand has contributed different kinds of harmful chemical and biological species in the atmosphere. Recently, air pollution has become a burning issue of common concern. The process of air pollution can be defined as the atmospheric conditions having high levels of pollutants which may produce undesirable effects on materials, plants, and human health. The major air pollutants include sulfur dioxide, nitrogen oxides, carbon monoxides, hydrocarbons and particulate matters, etc. which play a very significant role in affecting the biochemical and physiological processes of the plants and ultimately lead to yield losses (Heck et al. 1988). In developing countries like India, a very drastic change in the quality of air has been observed during past two decades. Many cities in Asia, Africa, Latin America are facing major challenges of air pollution (Ashmore 2005). Delhi (the capital city of India) is also facing the problem of severe air pollution in spite of the implementation of CNG-driven public transport (Saxena et al. 2012). The air quality in Delhi has been the worst among 1,600 cities of the world (WHO 2014–2015). According to the estimates, around 1.5 million people are killed every year. India has the world’s highest death rate from chronic respiratory diseases and asthma.