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Its Meteorological Administration dispersed clouds by firing rockets with chemicals into the sky, possibly contributing to a rain-free opening ceremony.

Russia uses the process to reduce the size of hail stones that would otherwise destroy vegetation. One hail stone, which can be up to the size of a small orange, dissipates into around twenty pieces after chemicals are added to it.

The chemicals increase the rate of condensation of extremely cold water droplets into hail, thereby reducing the size of the stones.

Rain enhancement, on the other hand, is practised in countries that experience frequent droughts. Australia has used the technology since 1947 and is trying to increase its water reservoirs in order to generate more hydroelectricity.

Instead of using planes to sprinkle clouds with chemicals, however, scientists place burners on the top of mountainous areas. The mini-furnaces use ethanol to burn the chemical silver iodide, which is then released into the atmosphere and quickly ascends into the clouds situated just above the mountains.

Although the cloud seeding technique is becoming widely popular, it is still in its experimental phase, says Gary Jones, CEO of eWater Cooperative Research Centre in Australia.

Jones says there are still "sensitivities" in areas of the technology. "Some people don't believe the technology really works," he explains. "What has never been proven in a proper trial is whether you can induce rain on a large scale - in a significant region or a watershed for example.

"Water utility companies who run the tests in Australia have been claiming a 10 to 30 percent increase of amount of rainfall, but that's never statistically been proven."

Another sensitive issue is that it is not entirely clear whether the chemicals used in cloud seeding cause harm to the environment. Silver iodide is a frequently used chemical in the process, but it is also a toxic metal, which, on the face of it, is hardly ideal.

Although the amounts of it used are "very little," Jones says there is a possible risk of pollution in soils accumulating. "That might be dangerous when you look at the situation after 50 or 100 years."

Farrah of the NCMS in Abu Dhabi disagrees.

"It's absolutely not dangerous for our environment. The amount of pollutant chemicals we add is less than 0.01 microgram per litre. The limit for it possibly becoming harmful is 50 mg per litre," he says.

In the UAE, silver iodide is only used when the atmosphere is very cold. According to the NCMS, around 30 percent of its tests are done on so-called ‘cold' clouds, where it is typically around minus 5 degrees Celsius.

The chemical process is different from the one described above which is used on ‘warm' clouds - those that are usually between 15-17 degrees Celsius.

When seeding ‘cold' clouds, raindrops are formed by making silver iodide ice crystals grow. They absorb water vapor, found around cold droplets, which were already present in the cloud.

The vapor causes the crystals to become liquid under the freezing level, thereby creating rain.

The possible risk of using silver iodide is certainly not the only challenge scientists face when experimenting with rain enhancement globally. Adding to the problem is the limited amount of suitable clouds that can be used for testing.

Meteorology centres cannot create clouds, or induce rain from clouds, that do not have the relevant characteristics.

"The problem in a lot of Middle Eastern countries is that the classic way to get clouds is [only after] formation over mountain ranges", explains Jones. "A group of Russian scientists has been traveling around the world claiming they can make clouds, but no one believed a word of it."

Farrah believes the lack of clouds is the biggest problem the scientists face.

"No clouds, no seeding", he says matter-of-factly. "But as long as we can, we will continue searching, and searching for ways to enhance the rain."

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