The summer has barely begun but incidents of fire in the forests of North India’s hill states, and in several urban and rural areas have registered a sharp rise. For instance, data by the Ministry of Environment shows that the number of forest fires recorded in the first four months of this year have surpassed the tally of such fires in the previous three years.
In Delhi, the fire department registered a 500% rise in the number of fire-related calls in April compared to the same period last year. One of the fires reported included the one that destroyed the National Museum of Natural History on April 26.
In Bihar, at least 66 people and 1,200 animals were killed in fires that have gutted 1,000 houses across six villages in the past two weeks. Following this, the state government issued an advisory that disallowed cooking in villages between 9am and 6pm to prevent any further outbreaks of fire.
The fire triangle
But what is the cause of all these fires?
The three basic ingredients for a fire are – oxygen, fuel and heat, which together form what experts call a fire triangle. The first two ingredients are always available round the year. But the third factor – heat – is the reason why outbreaks of fire are more common in summer than in winter, and register a sharp rise during heat waves than during a normal summer.
Add to this the drought conditions in several parts of the country and you have before you a deadly kindling. In Uttarakhand, for instance, where there are active fires in 100 places, it has barely rained since the last monsoon, and there was hardly any snow in winter too, which means the water courses are all dry.
The lack of rain coupled with increased evaporation in the summer leaves the soil in forests with very little moisture, said Vimal Mishra, scientist at the water and climate laboratory at the Indian Institute of Technology-Gandhinagar.
This lack of humidity helps propagate fires that start from a cooking stove or from other human activity. “If a person in a village wants to clear grass in his agricultural or pastoral lands, the idea is to have a controlled fire,” said Mishra. “But those fires become uncontrolled because of the dry conditions all around.”
But high atmospheric temperatures and aridity alone don’t cause fuels like twigs and straw to self-combust. It is not surprising to see the outbreak of fires in the current weather conditions, said GC Pant, Inspector General of the Uttarakhand Fire Services. But he added that there had to be a spark.
“Maybe someone was smoking a cigarette near the forest and he threw it without putting it off, and that provided the spark,” said Pant. “Or maybe it was just someone playing with a match. It could be anything but the loss is in crores.”
The wind ends up feeding the fire the oxygen it needs.
This is perhaps how several huts in Harinagar village near Aurangabad district in Bihar caught fire last month, killing 12 people. The fire started from a kitchen in one home and rapidly spread to nearby homes. The victims couldn’t escape fast enough.
Upendra Singh, commandant, Bihar Fire Services, said that though the huts were made of mud, they were covered with straw. “This catches fire easily in the absence of moisture in the surroundings,” he said.
He added that the Bihar government ban on cooking during the day was because of the ongoing heat wave. “It’s done for the benefit of people and others around them as fires in the summer spread much faster because of already high temperatures,” Singh said.
Urban blazes
In urban areas, experts said short circuits are among the leading cause of fires.
In Delhi, the fire department received more than 970 distress calls in April – up from 164 recorded in the same month last year. Besides the fire that destroyed the National Museum of Natural History, fires were reported from the Enforcement Directorate headquarters, a commercial centre in Pitampura, and a scrap warehouse. The causes of all these fires are yet to be ascertained.
“When there is extreme heat outside, usage of air conditioners goes up immensely in urban areas,” said Pant. “This adds to the load on electrical wires. Some of these wires are not designed to handle such a load and often trip, which produces the spark needed to start a fire.”
Pant added that that the quality of wires being used in homes and offices were also a factor. “Some wires are made of polymers, which melt on continued exposure to hot temperatures, which could also result in short circuits,” he said.
Fires in urban areas often spread rapidly because of the presence of combustible materials like paper and cloth in factories, offices and homes.
“People keep lots of unwanted materials… and these are often combustible,” said N Suresh, head of the Building Fire Research Centre at the National Institute of Engineering in Mysuru.
“If there is an electrical short circuit, the spread of fire will be very fast in hot temperatures because there is no moisture content in any material. They will be dry and as good as any fuel.”
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