Resumen
The contribution in rain acidification caused by the oxides of nitrogen which are further oxidised to nitrates and subsequently release of hydrogen ions in the atmosphere while reacting with rain droplets has been studied from the period 1976 to 1987 using the data of ten BAPMON stations of India. It was observed that there exists a significantly strong inverse correlation (r = -0.845 ± 0.083) between the rainfall pH and the corresponding concentration of nitrates at about 1% L. S. which indicates that rapid decrease in rain pH in India is mainly caused by the sudden increase in nitrate radicals which are formed by the oxidation of nitrogen oxides which are the ultimate outcome of automobile pollution caused by the rise in vehicular population in India.