Theory:

     WHO - Whoo, Whooo, cried the wind as it swept down from the Himalayan snows. It hurried over the hills and passes, and hummed and moaned in the tall pines and deodars.

     On Haunted Hill there was little to stop the wind–only a few stunted trees and bushes, and the ruins of what had once been a small settlement.

     On the slopes of the next hill there was a small village. People kept large stones on their tin roofs to prevent them from blowing away. There was nearly always a wind in these parts. Even on sunny days, doors and windows rattled, chimneys choked, clothes blew away.
 
     Three children stood beside a low stone wall, spreading clothes out to dry. On each garment they placed a rock. Even then the clothes fluttered like flags and pennants.
 
     Usha, dark haired and rose cheeked, struggled with her grandfather’s long loose shirt. She was eleven or twelve. Her younger brother, Suresh, was doing his best to hold down a bed-sheet while Binya, a slightly older girl, Usha’s friend and neighbour, was handing them the clothes, one at a time.
 
     Once they were sure everything was on the wall, firmly held down by rocks, they climbed up on the flat stones and sat there for a while, in the wind and the sun, staring across the fields at the ruins on Haunted Hill.
Explanation:
 
Have you ever heard the sound of the wind? It sounds like who, whoo, whoo. Here the author is telling about the Himalayan region full of snow, where we have tall pines and deodar trees. You can hear the sound over the hills.
 
The author is describing a hill, which he calls as haunted as there were people in those areas some years back, but there is no one there now only a few trees and bushes.
 
He is telling about a hilly region where we can always see a small village on the slopes of the next hill. People kept some large stones on the tin roof so that they doesn't blow away. In those area's whatever is the weather sunny or cold, there is always wind blowing and doors and windows rattled, chimneys choked, and clothes which were hung on clothe hanger blew away.
 
In that village, three children were drying their clothes. They kept a stone on each clothing so that it won't fly, but still, the clothes were fluttering.
 
Usha was one of them. She had dark hair and rosy cheeks. She was struggling to hold her grandfather's long loose shirt. She was just eleven/twelve years old. She had a younger brother named Suresh who was holding the bedsheet. Usha's friend and neighbour called Binya, who was older to Usha, was handing them clothes to dry.
 
Finally, they made sure that the clothes were held by rocks on the wall, after that they sat on a flat stone just looking at the fields and the ruined Haunted Hill.
 
Meanings of difficult words:
 
Numbers
Word
Meanings
1.
Hummed
Make a low, steady continuous sound.
2.
HauntedEerie.
3.
MoanedMake a long, low sound expressing physical or mental suffering.
4.
Fluttered
Flitter, dance.
5.
PennantsOne flown at the masthead.
6.
Staring Gazing.
Reference:
State Council of Educational Research and Training (2019). Term-1 English Standard-7. The Wind on Haunted Hill by Ruskin Bond (pp. 25-34). Published by the Tamil Nadu Textbook and Educational Services Corporation.