AIR

Water will flow from high to low. In human life water is needed because of the source of life. If Allah SWT does not create water then man can not survive as we feel today.
Falling water droplets can create a sound that can make the human heart cool, calm and can relieve fatigue and stress.
Thus we live in this world very highly dependent on the existence of water.
And also we must keep the water must always be healthy and clean. if clean water then our life is clean.