New delhi, Jan. 8 -- There's more to dense fog conditions than pollution and flight cancellations. There's also the risk of power outages. In fact, a perfect storm may be brewing across several parts of north and central India, where a rain-deficient winter, dense fog conditions and atmospheric pollution have raised concerns over the tripping of power transmission lines, said three people aware of the outage concerns in India's power system. Fog increases moisture on power transmission lines, allowing pollutants in the air to settle on their surface. Over time, dust and grime accumulate on these lines, reducing insulation strength and leading to flashovers (a high-voltage discharge where electricity "jumps" across an unintended path-usually through the air or over the surface of an insulator), short circuits and automatic tripping of transmission and distribution lines. If left unaddressed, such conditions can potentially lead to a grid collapse. The states at risk of power outages include Punjab, Haryana, Uttar Pradesh, Rajasthan, Delhi, Madhya Pradesh and Chhattisgarh. While rains are the natural cleanser for transmission lines and insulators, this hasn't been the case this year. Rainfall across the country in December was about 69% deficient compared to the 10-year average, according to data from the India Meteorological Department (IMD). Also, the deficit was wider in northwest India (84.8%) and the central region (99%). "This year, the winters have been rain-deficient, which has raised concerns. There were rains in the last winter season and it helped in terms of cleaning the insulators, thereby reducing outage concerns. While earlier helicopters were used for cleaning of the transmission lines and insulators; now it is largely done manually with the use of chemicals," said a power sector executive requesting anonymity. "The materials used for the overhead (transmission) systems do get impacted by the elements in polluted air. Because of these environmental issues, there are issues being faced and any system has to be insulated against these elements which come in their path," said Anil Razdan, former secretary in the power ministry. "We need to be cautious of the reaction or the reactivity of the environment. Sometimes insulation may also wear off due to acidic content in the environment. There has to be a constant health check and efficiency check of the systems." "India is witnessing more frequent and intense fog episodes this winter," IMD Director General of Meteorology Mrutyunjay Mohapatra said, attributing the trend to weak wind conditions and persistent western disturbances. In December, dense-to-very-dense fog persisted for 15-26 days, mainly across the Indo-Gangetic Plains covering Punjab, Haryana and Uttar Pradesh, Assam, Odisha and parts of the western Himalayan region, including Himachal Pradesh and Uttarakhand....