General Knowledge: Have you ever wondered what does it mean when the Meteorological Department says - "25 mm of rain fell in Delhi"? Or how is it decided that Mumbai has the most rainfall? Know the science that keeps track of every drop... and find out where the clouds have rained the most so far this monsoon.

General Knowledge: As soon as the monsoon season arrives, everyone's eyes are on the Meteorological Department's report. Someone asks, "How much rain fell today?", then someone says, "100 mm of rain fell in Mumbai, there was just a light drizzle in Delhi." But have you ever wondered how they measure rain? And what does it mean in millimeters?

Method of measuring rain

The Indian Meteorological Department (IMD) measures rain in millimeters (mm). For example, if it is said that Delhi received 20 mm of rain, it means that an open vessel placed on a level ground was filled with 20 mm or 2 cm of water – provided that the water did not overflow or seep into the ground.

Rain Gauge: An instrument to measure rain

An instrument called rain gauge is used to measure rain. It is a cylindrical container in which rain water collects. The amount of water collected in it is considered as rain. This figure is noted in millimeters.

IMD's network and reports

IMD has thousands of rain gauge stations in India, which are installed in every state and city. Through these, every small and big activity of rain is recorded. Apart from this, the Meteorological Department prepares daily, weekly and seasonal reports with the help of satellite, Doppler radar and computer models.

Where and how much rain has occurred so far this year?

Mumbai: So far in June, about 1200 mm of rain, which is slightly more than normal.

Delhi: Around 200 mm of rain, close to normal.

Kolkata: After a slow start, records over 500 mm of rain till July.

Where to get the information?

These updates are conveyed to the general public through IMD's website, mobile app and news channels.