Heat waves in India are declared when the maximum temperature of a station reaches at least:
- A35°C for plains and 25°C for hill stations
- B40°C for plains and 30°C for hill stationsCorrect
- C45°C for plains and 35°C for hill stations
- D38°C for plains and 28°C for hill stations
Explanation
Correct. According to the IMD, a heat wave is declared when the maximum temperature of a plain station reaches at least 40°C (or 30°C for a hill station), along with a departure of 4.5°C or more from normal.
Why the other options are incorrect
- Option A
The threshold of 35°C is too low for a heat wave declaration in the plains. The IMD criteria require at least 40°C.
- Option C
45°C exceeds the base threshold. While 'severe heat wave' criteria involve higher departures from normal, the base temperature for heat wave declaration in plains is 40°C.
- Option D
38°C is not the standard threshold used by IMD for heat wave declarations.