How do Countries like UAE and China create Artificial Rain?

Heat from the sun warms the water, turns it into water vapours, and the process is called evaporation. The vapours of water rises up, their temperature cools down. When the water vapour cools they change back into tiny water droplets. And the process is called condensation.The tiny water droplets make clouds.

The tiny droplets of water in cloud don't bump into each other because they are in purest form of water. As clouds move some dust particles get in and the tiny water droplets stick to dust particles and form bigger droplets and when the droplets get heavier they fall on Earth as rain. 

*Now what is cloud seeding?* 

It is a technique developed in 1946 by Vincent Schaefer. In this technique silver iodide is sprayed on clouds and silver iodide works same as dust particles and stick small water droplets together and from bigger droplets hence this cause rain.In 2008 China got chance to host summer Olympics 2008. China spent massive amount for this event. They build new stadiums, renovated Beijing airport and improve public transport.There were just two days left for opening ceremony of Olympics, everything was ready. Teams from every country of the world were there, but Chinese government got very shocking news, that Beijing will have heavy rainfall on the day of Olympic opening ceremony. The real tension on Chinese government was that the stadium was open air stadium.Chinese government found an interesting way to stop the rain from falling in Beijing. On the day of event when clouds were on their way to Beijing, China used cloud seeding method, before clouds reach Beijing. It started raining out of Beijing and the event happened without any problem.