New Delhi/Shimla, Oct. 6 -- The Himachal high court on Monday stopped operation of two anti-hail guns in apple rich Deorighat and Bareonghat in the Jubbal-Kotkhai area of Shimla district in Himachal Pradesh for at least one year to study its implications. A bench of chief justice GS Sandhawalia and justice Bipin C Negi passed the directions after the state informed the court that a study was being conducted on efficacy of the anti-hail guns by the Dr YS Parmar University of Horticulture and Forestry, at Solan. The study is to find the ecological and environmental implications of use of anti-hail guns as farmers have alleged that the guns have may have reduced hail in areas, where it is installed, but has increased impact of hail in other areas. The YS Parmar University will take at least four more years to reach a definitive conclusion, the court was told. The matter will next come up for hearing on December 8. Hail is produced by cumulonimbus clouds, which are generally large and dark and may cause thunder and lightning. In such clouds, winds can blow up the water droplets to heights where they freeze into ice. The frozen droplets begin to fall but are soon pushed back up by the winds and more droplets freeze onto them, resulting in multiple layers of ice on the hailstones. This fall and rise are repeated several times, till the hailstones become too heavy and fall down. According to IMD data in 2024, there are roughly two to three hailstorms per year over east Madhya Pradesh, west and north Bihar, and extreme northeast Assam, six over west Uttar Pradesh, and parts of east Bihar, and 10 hailstorms per year on average (light, moderate, and heavy). Madurai, which saw one to two hailstorms in April and May, was reported to have the highest activity in the southern peninsula. The northwest and northern regions of the country experienced the most hailstorm activity during the months of April and May, with an average of 50 hailstorms in a period of 75-80 days. The hailstorms, whose frequency is believed to have increased in recent decades, damages grain, vegetable and fruit quality causing fall in its market price. About 85% of the Himalayan populace is directly or indirectly dependent on traditionally practiced integrated hill agriculture and agroforestry for livelihood, according to a 2024 study YS Parmar University. Karunya Institute of Technology and Sciences, Coimbatore, in a 2024 study estimated the loss can vary year-wise depending on intensity, adding that hailstorms were common over large areas in Maharashtra, Himachal and Assam. As advance hail warning can only be of about 15 minutes, preventing damage to crops becomes difficult. However, in this period operating an anti-hail gun is possible. A machine that generates shock waves to disrupt formation of hailstones in clouds, according to the makers of the machine. The machine has a base and several meter high cone shaped top to fire the explosive mixture, which is acetylene gas. The acetylene gas canon is pushed into the lower chamber having air and is fired, releasing a shock wave. The conical barrel directs the shock wave towards the hail cloud. The waves, manufacturers claim, move faster than speed of sound and prevents water droplets in the cloud from forming into ice. The anti-hail gun is fired repeatedly at the approaching thunder storm. The shock waves force the water droplets to fall down before they can be lifted by the updrafts for ice formation. The timing of the firing is key to prevent the hail storm. It has to be fired just when droplets are being lifted. A delay can cause a misfire. In some places in Himachal, the anti-hail guns have failed to deliver forcing the government to stop its use. However, the ones at Deorighat and Bareonghat are still functioning. Anti-hail gun efficacy is a contentious issue. While apple orchard owners around Deorighat and Bareonghat claimed that the guns have worked, many in some distance away claim that it has resulted in more intense hail storms. "We have seen very less hail storms since the gun was installed more than 15 years ago. Even if there is hail, it is very light," said Gobind Chauhan, a farmer whose apple orchard shares boundary with the anti-hail gun installed at Deorighat. Despite the gun, several farmers in the region install anti-hail nets over apple trees every year. The reason that even light hail damages the quality of apple produce. "Even a dot on an apple can reduce by the price by 20%. That is the reason I spend over Rs one lakh every year to install the nets over trees in March-April, when hail storm starts," said Vardhan Chauhan, who lives about five kilometers away from Deorighat. The nets are removed during monsoon as hail storms are mostly caused by western disturbances. The Himachal government informed the high court that the university has not collected sufficient rain data to reach any conclusion. The university with Indian Institute of Technology, Bombay, is collecting data on rain (hail) variance after firing of the canons since June 2021, in a first long-term scientific study on efficacy of the guns. It needs another four years reach a conclusion....