A balloon release occurs when a number of hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 or helium

Helium

Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...

-filled balloon

Balloon

A balloon is an inflatable flexible bag filled with a gas, such as helium, hydrogen, nitrous oxide, oxygen, or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene, or a nylon fabric, while some early balloons were made of dried animal bladders, such as the pig...

s are allowed to float into the sky together, or in rapid succession. This may be done for fun, to create a photo opportunity to raise awareness of a cause or campaign, or as a competitive race.

Balloon races

A balloon race or balloon flight contest is a competition wherein the competitors attempt to send balloons as far as possible. Postcard

Postcard

A postcard or post card is a rectangular piece of thick paper or thin cardboard intended for writing and mailing without an envelope....

s are attached to the balloons which are then released. The flight of the balloons cannot be influenced by the competitors. Instead, success in the contest is dependent on the wind conditions and on the location in which the balloon lands. The contest depends on the goodwill of passers-by to find the balloons and return the postcards. A prize may be awarded to the person whose balloon travels the furthest.

Opposition

A number of organisations (for example, in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, these include the Marine Conservation Society

Marine Conservation Society

The Marine Conservation Society a UK charity for the protection of the seas around the United Kingdom, and for the protection of their shores and wildlife.According to their website MCS's Vision is:Their website also states:...

, the Royal Society for the Prevention of Cruelty to Animals

Royal Society for the Prevention of Cruelty to Animals

The Royal Society for the Prevention of Cruelty to Animals is a charity in England and Wales that promotes animal welfare. In 2009 the RSPCA investigated 141,280 cruelty complaints and collected and rescued 135,293 animals...

, the Tidy Britain Group, the National Farmers Union and the RSPB) oppose balloon releases, because of the visual impact of the fallen, deflated balloons, and the risk of harm to wildlife and domestic animals which they pose.

For these reasons, balloon releases are prohibited in some jurisdictions.

Permissions

Within many countries written permission is often required from the relevant airspace regulatory authority. In the UK this would be the Civil Aviation Authority

Civil Aviation Authority

This is a list of national and supra-national civil aviation authorities.-See also:* Air route authority between the United States and the People's Republic of China* National Transportation Safety Board -External links:****...

, for releases over a certain number of balloons.