A heatwave is sweeping across large parts of India
The India Meteorological Department (IMD) has said that a "faulty sensor" gave an erroneous recording of 52.9 degree Celsius on May 29. The sensor had a "positive bias" of 3 degree Celsius (over reading by three degree Celsius), a team of specialist concluded. So in essence, the temperature should have been 49.9 degree Celsius, which is still very hot, but not record-breaking.
Union Earth Sciences Minister Kiren Rijiju in a post on X said stringent quality control should be applied before releasing such data.
A team headed by IMD scientist Ranju Madan said the temperature sensor at the Mungeshpur automatic weather station (AWS) reported 3 degree Celsius (higher maximum temperature than the maximum temperature reported by the standard instrument).
They said the comparison of maximum temperature reported by AWS stations at other locations with departmental manual surface observatories in Delhi showed no significant difference. So the maximum temperature reported by AWS Mungeshpur was not correct due to malfunctioning of the sensor.
According to the IMD, the maximum temperature in Delhi-National Capital Region (NCR) is being monitored through five surface observatories and AWS. The observations of maximum temperature on May 29 were between 45.2 and 49.1 degree Celsius, except the AWS installed at Mungeshpur, which reported a maximum temperature of 52.9 degree Celsius.
On May 29 itself, NDTV reported the IMD is checking the temperature sensor at the Mungeshpur AWS to see if the sensor is working properly, which was confirmed by IMD Director General M Mohapatra. This weather station's reading was the highest ever in India.
Dr Mohapatra had said there are 20 monitoring stations in Delhi and of these, 14 have recorded a drop in temperature and the average seen across Delhi was in the range of 45-50 degree Celsius. He had said the Mungeshpur station was an "outlier", and the recording needed to be confirmed.
Some observatories in Delhi had shown a slightly higher temperature, but the Mungeshpur recording needed a full investigation.
A team of specialists had gone to Mungeshpur to check the temperature sensor, Dr Mohapatra had said. He had also speculated it could be local factors around Mungeshpur that could be the cause for the high recording.
"The maximum temperature over Delhi-NCR varied from 45.2 to 49.1 degree Celsius in different parts of the city. Mungeshpur reported 52.9 degree Celsius as an outlier compared to other stations. It could be due to error in the sensor or the local factor. IMD is examining the data and sensors," the IMD said late on May 29 evening.
The Earth Sciences Ministry says necessary remedial measures are being taken up by IMD to avoid errors in AWS.
In a rare admission, the head of the weather office said, "We learn lessons from mistake."