They say that one ought to replace the fear of the unknown with curiosity. And that’s exactly what residents of Mumbai did on that miraculous day in 2006. In a strange case, an extraordinary phenomenon took place on 18 August 2006 in Mumbai which still continues to be a topic of interest to this day. The usually salty seawater turned sweet in Mumbai that day. Curious people thronged to the shores to get a sip of the water that eventually attained the status of “holy water.”

In 2006, a strange phenomenon happened in Mumbai, India. Residents claimed the waters in the Mahim Creek had surprisingly turned sweet for almost a day! Within hours, residents near Teethal Beach in Gujarat also claimed that the water there tasted sweet too. 

The incident started on the night of 18 August 2006. The water around the Makhdoom Ali Mahimi Dargah located near the Mahim creek in Mumbai suddenly started turning sweet. Brihanmumbai Municipal Corporation (BMC) conducted tests and found that the water had only 600 particles per million of salinity as opposed to the usual 10,000 particles per million. When local people started talking about it, the news spread like wildfire. By midnight, people from all over Mumbai flocked to the shores of Mahim Beach to get a taste of this sweet water.

Within just a few hours, reports started pouring in from Gujarat that the waters at Teethal Beach have also turned sweet. There too, residents came in large numbers to get a taste of this miracle.

This led to mass hysteria among people claiming the phenomenon to be a miracle. People were seen drinking the water and collecting it in bottles to take home. Despite warnings from health officials that the water might be harmful, people kept drinking what they called the “holy water.”

As with any rare phenomenon, the seawater turning sweet was seen as a miracle by the local residents. With news spreading like wildfire about the “holy water,” thousands of people came to the shores to drink it. Since the water turned sweeter near the Makhdoom Ali Mahimi Dargah, locals saw it as a blessing from the 13th-century Sufi Saint Makhdoom Ali Mahimi.

There were strict warnings from officials not to drink the water. Vilasrao Deshmukh, Chief Minister of Maharashtra, India, also appealed to the people to not drink the water, but no one gave any heed to the warnings. The water in that area is known to receive tons of raw sewage and waste from industries every day. People were drinking, bathing, and collecting the water in vessels and bottles despite garbage floating all around. Officials feared that drinking such polluted seawater might lead to a severe outbreak of water-borne diseases like gastroenteritis.

Fortunately, there were no reports of any diseases or outbreaks.

Although the exact cause of the phenomenon is not known, officials say that it was a natural phenomenon. Due to heavy rainfall, a large pool of fresh water might have flowed into the sea making the water less salty. 

According to the geologists from Indian Institute of Technology Bombay, the water turning sweet is nothing but a natural phenomenon. Mumbai experienced heavy rains just a few days before the phenomenon. This might have caused a pool of fresh water to accumulate in a rock formation underground near to the shore. Due to the difference in densities, the pool of fresh water must have risen to the top of the sea water and spread across the shores. This would make the water near the shore taste sweet. In a couple of days, the two would mix returning everything back to its normal state.

There were other explanations as well. The National Institute of Oceanography said that the sweetness might have been due to the reduction of contamination of the seawater as a result of the Mithi River flowing into the Mahim Creek. As for Gujarat, Valsad District Collector, D. Rawal, said that the reason could be the heavy monsoon. The two rivers, the Auranga and Banki, were flooding, and the excess water was flowing into the ocean. Again, due to a difference of density, the sweet, fresh water might have risen to above the level of the salty seawater.

After about 14 hours, people started saying that the water had started turning less sweet. At 2 p.m. the next day, the water returned to being normal, that is salty and undrinkable.

At 10.30 a.m. on 19 August 2006, the tide changed and people started saying that the water had turned “less sweet.” At around 2 p.m. on the same day, everything seemed to turn back to normal again. Although there has been no concrete answer as to what caused the phenomenon, it was a remarkable day for the local residents who will continue to talk about it for a long time.
[Sources: 1, 2, 3, 4]