Kartik Snan, holy dip during Kartik mahina, is most sacred ritual during the month performed along the river banks of Yamuna, Ganga, Brahmaputra and some other holy rivers of South and Western India. Kartik Snan and Deepadaan are widely observed throughout the month of Kartik in holy places like Kasi (Varanasi) and Allahabad. But, the main concern for Hindu devotees is mud and slush filled rivers banks of Yamuna.

Mrigank Tiwari writes for Times of India:

• Even as save Ganga activists are raising the issue of the growing pollution in the holy river, the banks of Yamuna are also in need of attention even as the auspicious month of Kartik has commenced from Monday. If the timely steps are not taken, the pollution may jeapardise the `kartik snan’ of pilgrims, who throng the banks of the Yamuna to take a holy dip and remain free from diseases.
• As per mythological traditions, people consider it important to take a dip in the Yamuna during the month of Kartik. Explaining the importance of month of Kartik, astrologer and religious teacher Girija Shankar Shastri said that Sun is in a transit position to Libra (Tula). However, it is considered a retrogate position which is not very auspicious. It result in diseases and death because the first 15 days of the month are considered to be the days of Yamraj, the god of death. In order to appease Yamraj and save themselves from his wrath, people take a holy dip in the Yamuna, who is the twin sister of Yamaraj as per mythology.
• Women perform `deepdaan’ by lighting earthen lamps as sun rays lose vitality and power during this month. Therefore, `deepdaan’ is performed to compensate for that loss. A legend says that during the month of Kartik, the Yamuna possesses divine powers to energise the body, added Shastri.
• The banks of the Yamuna in the city are filled with mud and slush. The rains have further aggravated the situation. It is nearly impossible to reach the the river as the concrete steps constructed along the banks are covered with mud and sand, making it difficult to move safely. With the heavy rush of devotees expected on the banks during this period, the `snan’ would become arduous, said Alka Mishra, who is a regular bather during the month of Kartik for the past several years.