Explanation:

The Clean Survey-2023 is a survey conducted to assess the cleanliness and pollution levels of the cities located along the Ganga River in India. It aims to promote the cleaning and conservation of the Ganga River and recognize the efforts of cities in maintaining cleanliness.

The Cleanest Ganga City award is given to the cities that have shown outstanding performance in maintaining cleanliness and reducing pollution levels in and around the Ganga River. In the Clean Survey-2023, the two cities that have received the Cleanest Ganga City award are Varanasi and Prayagraj.

Reasons for Varanasi receiving the Cleanest Ganga City award:
- Varanasi is one of the oldest and holiest cities in India, attracting millions of tourists and devotees every year. The city has made significant efforts to maintain cleanliness and reduce pollution levels in the Ganga River.
- The city has implemented various initiatives and projects to treat and manage wastewater effectively. This has resulted in a significant improvement in the water quality of the Ganga River in Varanasi.
- Varanasi has also taken measures to prevent open defecation along the riverbanks and promote the use of public toilets. This has helped in maintaining the cleanliness of the river and its surroundings.
- The city has actively engaged in awareness campaigns and community involvement programs to educate the residents and visitors about the importance of keeping the Ganga River clean.

Reasons for Prayagraj receiving the Cleanest Ganga City award:
- Prayagraj, formerly known as Allahabad, is another important city located along the Ganga River. It is famous for the Kumbh Mela, a major Hindu pilgrimage that attracts millions of people.
- The city has implemented effective waste management systems and has taken measures to control industrial and domestic pollution in the Ganga River.
- Prayagraj has also focused on maintaining the cleanliness of the riverbanks and promoting eco-friendly practices among its residents and businesses.
- The city has actively worked towards reducing the discharge of untreated sewage and industrial effluents into the Ganga River, leading to improved water quality.

Overall, Varanasi and Prayagraj have demonstrated exemplary efforts in maintaining the cleanliness of the Ganga River and its surroundings. These cities have implemented various initiatives, engaged in awareness campaigns, and focused on effective waste management to ensure the conservation and cleanliness of the Ganga River. As a recognition of their efforts, they have been awarded the Cleanest Ganga City award in the Clean Survey-2023.