CHANDIGARH - Fog in September? Sounds strange, but it's true. On Wednesday morning, Ambala in Haryana, and from Zirakpur to Ludhiana in Punjab experienced poor visibility due to fog.

For the past three days, Banur resident Surinder Singh has been wondering why visibility on roads is low. Surinder, a carpenter, has never seen fog in September. "It's strange despite such high day temperature, there's fog early in the morning," he said.

Affirming this phenomenon, officials at the meteorological department, Chandigarh, informed that visibility in Ambala was barely 800 metres, whereas in the city it was 2.5 kilometres. The maximum temperature recorded in the city was 35.2 degree Celsius. "The air is laden with 95% moisture. On Wednesday morning, in Ambala, people could see up to 800 metres with naked eyes," said Rajinder Singh, scientific assistant at UT's meteorological centre. He added that apart from Ambala-Rajpura stretch, Sarsawa, near Saharanpur in western UP also experienced fog.

Met officials and city-based environmentalists said this climatic condition was 'rare'. "Earlier, we had experienced mist and haze during this season, but fog is rare. It's been happening since the last three days. However, it's a natural phenomenon. Humidity is present in the atmosphere. Low speed of winds, stable weather and a plunge in the morning temperature make a perfect condition for fog to occur. Fog can also happen because of more moisture in the air and a clear sky," said Chatar Singh, director of UT's meteorological centre.

Agreed professor RK Kohli, an environmentalist, "Abrupt changes in climate are expected. Though fog is rare in September, but it can be due to heat entrapment in atmospheric layers. This is also a result of global climate change."