Atash [Atash] (firework) a device containing explosive chemicals that burn or explode, used specially at celebrations. The display of atash is termed as ataxbaji. From ancient times, various nations and religious communities have been using atash to celebrate victory and at religious functions. As early as the 9th century, the Chinese used gunpowder in atash and it was they who brought atashbaji to a high stage of development. Many combustibles and explosives and ingenious combinations of the two have been devised to produce impressive sounds and light of many colours. Among them potassium nitrate, sulphur, iron-dust and charcoal powder are important elements of atash for producing speed and sparks.

To increase the intensity of the explosion, a limited amount of gunpowder is also added. Again, nitrate of lead and powder of barium and Aluminium are mixed with the ingredients to increase the brightness of light. Various kinds of metallic salts are mixed with the potassium chlorate or perchlorate to make special atash with a view to creating colourful moving stars or attractive scenarios.

The use of atash for display is popular throughout the world. In many countries atash is used to celebrate national days, eg independence day and victory day. In Bangladesh atashbaji like tarabaji, tubri, charkibaji, kadamjhar, phuljhuri are used in various religious, social and national functions. Old Dhaka has some expertise in making atash. Usually, the elements are put in a paper packet but for important big occasions Bangladesh imports atash from foreign countries. Atash is also widely used as a signalling device, eg red flares to stop trains, and various coloured flares and smoke grenades to denote distress or to locate targets in military operations. [Md Mahbub Murshed]