Immersion of Kali idols was kept on hold for about 30 minutes on Tuesday night at all ghats along the Hooghly as the water level started to rise owing to a spring tide in the river, a Kolkata Municipal Corporation (KMC) official said.
A queue of about 25 idols had formed at Baje Kadamtala Ghat during the period from 9.50pm to 10.20pm when the immersion was suspended.
The Perigee Spring Tide — bhora kotal in Bengali — causes the water level in the Hooghly to rise more than the usual high tide level.
Immersions were kept on hold during the spring tide for the safety of the people involved in the ritual as well as those engaged in retrieving the idol frames and other objects from the river.
The 30-minute window when the immersion was stopped was not when the high tide was at its peak. Rather, it coincided with the end of low tide and start of high tide.
“The water current in the river remains very high during the transition from low to high tide. At the start of Perigee Spring Tide, it remains dangerously high. So, as a precaution, immersion was kept on hold,” said the KMC official.
"Water can rise about 6 metres at the peak of Perigee Spring Tide. The rise is about 2.5 metres in the first 30 to 45 minutes of the tide. So we need to be careful during this period,” said an official of the port trust.
“All launches tethered to the jetties are asked to leave before the start of Perigee Spring Tide. If they remain tethered, the force of the water can break the jetty.”
On Tuesday evening, water from the Hooghly had advanced about 3 metres up the cemented slope at Baje Kadamlata ghat.
At other ghats, several steps leading to the river were under water during high tide.
On Wednesday afternoon,too, The Telegraph found the slope at Baje Kadamtala Ghat partially under water during high tide.
The sandbags at the base of the slope — kept there to ensure that people carrying idols did not slip in the mud — were inundated.
“Immersion resumed once the initial phase was over,” the KMC official said.
Usually, people have to be very careful while stepping into the river from a cemented ghat.
The muddy stretch at the point where the steps end needs to be navigated with extreme care, which is why the immersion process takes time. But when the steps are under water, one can immerse an idol without having to step on the muddy stretch.
This speeds up immersion.
“Thrice the number of idols can be immersed in an hour during high tide compared with the count during low tide,” said the KMC official, who has supervised immersions for several years.
Over 1,100 idols were immersed on Tuesday and early on Wednesday.
A phenomenon called mora kotal, which is opposite of Perigee Spring Tide, had slowed immersion of Durga idols this year. During mora kotal — or diminished high tide — the water level remains very low in the Hooghly.