For the ______ time in 2015, surface ozone pollution in Delhi has crossed the permissible limit.

a. First

b. Second

c. Third

d. Fourth

ANSWER: Second

Explanation:

For the second time this year, surface ozone pollution in Delhi has breached permissible limits with weak monsoon being blamed for the phenomenon. While ozone layer limit in Mumbai and Pune is within permissible limits, it is also rising in these two cities. Delhi’s surface ozone pollution has crossed the threshold level it normally did in May June again, according to IITM scientists. Permissible limit is 50 ppb (8 hour day average) according to the monitoring carried out under SAFAR (System of Air quality and weather Forecasting and Research) system of Ministry of Earth Sciences.