thank you. coming up, a wildfire in one of the nation s most iconic national parks has doubled in size in a day. it s now within miles of y yosemite s sequoia trees. e an expedia member, you can instantly start saving on your travels. so you can go and see all those, lovely, lemony, lemons. and never wonder if you got a good deal. because you did.
A team was sent in to Mariposa Grove to wrap some of the massive tree trunks in fire resistant foil. The rest of the iconic park remains open though thick smoke hangs in the air.
thought they would see. the threat made worse by another year of drought, leaving the sequoias drive and vulnerable. that means its water source has been there for over 2,000 years. that that water is not there means that the climate and the world around it has changed. reporter: but lessons learned last year helped save some sequoia this year. before the castle fire, we had never seen losses of large trees like we had in that fire. 7,500 to 10,600 large sequoias lost in a single fire event. and that really changed what we decided we were willing to do to protect trees, if we could. reporter: and what they were willing to do called for innovation in the face of fire. from literally throwing what they could at the threat, like sprinkler systems that spray trees 35 to 40 feet in the air, and dropping fire retardant gel from aircraft into hard-to-reach groves, to extreme tree hugging,
swaddling some of the world s largest trees, like general sherman and general grant, in structure wrap. we had hand crews going and doing this kind of raking and fuel removal around individual trees in groves. we did backfire operations to change fire behavior. reporter: but the loss of any sequoia, such rare and majestic beauties is one too many to lose. it is dead. that tree is dead. it is not coming back. this tree that is at a minimum a thousand years old and has survived many, many, many previous fires and should have lived another thousand to 2,000 years is dead. is gone. reporter: stephanie elam, cnn, the sierra nevada mountains. in india, commuters make their way amid heavy smog as anti-smog guns spray water to curb air pollution. air pollution that s so bad, officials are considering restricting the use of private vehicles on alternate days. schools in the indian capital
world s sequoia trees from wildfires. we ll have a report from california coming up, and a new list is ranking the world s most polluted cities. who tops the list and how the government plans to fix it. stay with us.