Odisha Chief Minister Naveen Patnaik is on Thursday set to conduct an aerial survey of flood-affected areas of the Mahanadi river basin as around five lakh people in 12 districts are reeling under the deluge.

Special Relief Commissioner (SRC) P K Jena said the CM will take stock of the flood situation in the Mahanadi river delta region.

Kendrapara, Jagatsinghpur, Khurda, Puri and Cuttack districts are the worst hit by the calamity.

The chief minister had earlier asked officers concerned to ensure "zero casualty" in the flood caused by heavy rainfall due to a week-long low pressure and depression.

The state government has received reports of missing of two minors from Cuttack and Balasore, and the district collectors concerned are enquiring about the information, Jena said.

The meteorological department said a low-pressure system has been formed over northeast and adjoining areas of the east-central Bay of Bengal.

The Met office, in its 9 am bulletin, said it is likely to move east-northwestwards and become more marked during the next 12 hours and turn into a depression during the subsequent 24 hours.

The state government is now gearing up to deal with the possible situation of another spell of heavy rain due to the fresh low pressure formed on Thursday, the SRC said.

As the meteorological department has predicted heavy rainfall in north Odisha, the government asked district collectors of Mayurbhanj, Keonjhar, Balasore, Bhadrak and Jajpur to remain on alert.

"DCs of the northern states have been instructed to monitor the situation even though we do not see any flood in north Odisha," the SRC said, adding that water flow will be maintained within nine lakh cusec at Mundali barrage near Cuttack.

Over 4.67 lakh people in 12 districts have already been affected by the flood in the Mahanadi river system, another official said.

Water Resource department chief engineer B K Mishra said the water level in Hirakud reservoir declined to 624.43 feet at 11 am from 625.10 feet at 6 am.

Mishra said the water level at Mundali barrage also declined to 1,010 lakh cusec (cubic feet per second) at 9 am as against 10.18 lakh cusec three hours before.

The chief engineer said the government is currently not planning to close gates of Hirakud reservoir to regulate water flow in the downstream in view of the possible heavy rainfall as forecast by the meteorological department.

“Any decision on closure of gates will be taken by Thursday evening,” he said, adding that six gates, in the first phase, may be closed.

Mishra said seven breaches on the embankments of the Mahanadi river and its tributaries have been created.

Workers have been deployed to repair breached embankments,” the official said.

The Special Relief Commissioner stated that more than two lakh people in 10 districts were affected by the calamity.

Over 2.26 lakh people remained marooned in 425 villages, while around 54,000 have been evacuated and taken to shelters by Wednesday, he said.

Residents of 1,757 villages and 10 urban areas are reeling under the deluge.

With flood water inundating more villages, the state government has strengthened rescue teams of the National Disaster Response Force (NDRF), Odisha Disaster Rapid Action Force (ODRAF) and Odisha Fire Service.

The flood-hit districts are Angul, Bargarh, Boudh, Cuttack, Jagatsinghpur, Jajpur, Kendrapara, Khurda, Nayagarh, Puri, Sambalpur and Subarnapur.