Ludhiana, April 9 -- The city experienced its first heatwave on Tuesday as mercury soared to 40degC.

The IMD has issued a yellow alert for Ludhiana. According to the director of IMD's Chandigarh centre, Surender Paul, the heatwave will last till April 11 with daytime temperatures crossing the 40degC mark.

"The temperature, on April 8 and 9 in particular, will stay around 40degC or even above, which is way higher than the normal of 34degC for this period," he said.

A heatwave is a phenomenon when the temperature crosses 40degC and is higher than 4.5 Celsius to the normal, according to Paul.

Above 45degC is considered a moderate heat wave and above 47degC is a severe heat wave.

However, the temperature is expected to return under the h...