*Annual Arithmetic mean of minimum 104 measurements in a year taken twice a week 24 hourly at uniform interval

**24 boudy/8 hourly or 01 hourly monitored values, as applicable, shall be complied with 98% of the time in a year. 2% of the time, they may exceed the limits but not on two consecutive days of monitoring.


Whenever and wherever two consecutive values exceeds the limit specified above for the respective category, it shall be considered adequate reason to institute regular or continuous monitoring and further investigations.

Source: CPCB