"The flood water has started receding. We hope it will recede further during the day," state Revenue and Disaster Management Minister Surya Narayan Patro told IANS.
Although the situation in some worst-hit areas continued to remain grim, it is under control," he said.
Heavy rain brought by cyclone Phailin that hit the state coast Saturday night triggered floods in the districts of Balasore, Mayurbhanj, Jajpur, and Bhadrak, leaving a large number of people stranded.
More than one million people were affected when the water of major rivers and their tributaries in the region submerged low-lying areas, and swamped homes.
The worst hit is the district of Balasore where 68,000 people have been evacuated so far, Patro said.
More than seven lakh people were affected in this district, he added.
Many houses were under seven to eight feet of water, and the residents were forced take shelter on the roof top. Three air force helicopters would continue to airdrop food packets in the worst hit area for the second day Tuesday, he said.
Besides the army, the National Disaster Response Force (NDRF), Odisha Disaster Response Force (ODRF) and the state police personnel have been engaged in relief and rescue operation.
The situation in some areas of other three districts also remained grim, a senior state revenue department official said.
The very severe tropical cyclone in the Bay of Bengal which made landfall Saturday night near Gopalpur in Odisha's Ganjam district has left behind a trail of destruction in coastal districts of Odisha.
The worst hit districts include Ganjam, Puri, Khordha and Gajapati.
Although damage to properties was estimated at many crore rupees, the loss of human lives was minimal in comparison to the 1999 super cyclone, in which more than 10,000 people were killed.
The toll due to the latest cyclone and flooding stood at 21 so far. The low causalty figures were due to large-scale evacuation before the disaster, officials said.
More than 10 lakh people from the low-lying areas of the coast were evacuated and sheltered in safer places hours before the cyclone made landfall.
While some of them returned to their homes, large numbers of people were still living in relief camps and cyclone shelters as their houses were damaged.
According to preliminary government estimate, the cyclone and flood has affected more than a crore people in the state. More than two lakh houses have been damaged in the worst cyclone that hit Ganjam district.
Photos: Shah Rukh Khan, Rekha at a prestigious awards event
Oscars 2017: Emma Stone, Nicole Kidman, other stars on red carpet
Photos: Varun Dhawan, Alia Bhatt, Amitabh Bachchan walk the ramp
Photos: Priyanka Chopra at Oscars 2017 red carpet
Photos: Ranveer Singh, Ajay Devgn spotted at Mumbai airport