Tower of Silence
A dakhma (), also known as a Tower of Silence, is a circular, raised structure built by Zoroastrians for excarnation (that is, the exposure of human corpses to the elements for decomposition), in order to avert contamination of the soil and other natural elements by the dead bodies. Carrion birds, usually vultures and other scavengers, consume the flesh. Skeletal remains are gathered into a central pit where further weathering and continued breakdown occurs. History. The discovery of ossuaries in both Eastern and Western Iran dating to the 5th and 4th centuries BCE indicate that bones were sometimes isolated , but separation occurring through ritual exposure cannot be assumed: burial mounds, where the bodies were wrapped in wax, have also been discovered. The tombs of the Achaemenid emperors at Naqsh-e Rustam and Pasargadae likewise suggest non-exposure, at least until the bones could be collected. According to legend (incorporated by Ferdowsi into his ; ), Zoroaster himself is interred in a tomb at Balkh (in present-day Afghanistan). Zoroastrian exposure of the dead is first attested in the mid-5th century BCE "Histories" of Herodotus, but the use of towers is first documented in the early 9th century CE. The doctrinal  rationale for exposure is to avoid contact with earth, water, or fire, all three of which are considered sacred in the Zoroastrian religion. One of the earliest literary descriptions of such a building appears in the late 9th-century Epistles of Manushchihr, where the technical term is , 'ossuary'. Another term that appears in the 9th- to 10th-century texts of Zoroastrian tradition (the so-called "Pahlavi books") is ; in its earliest usage, it referred to any place for the dead. Rationale. Zoroastrian tradition considers human cadavers and animal corpses (in addition to cut hair and nail parings) to be "nasu , i.e. unclean, polluting. Specifically, the corpse demon (), is believed to rush into the body and contaminate everything it comes into contact with. For this reason, the (an ecclesiastical code whose title means, 'given against the demons') has rules for disposing of the dead as safely as possible. Moreover, the requires that graves, and raised tombs as well, must be destroyed. To preclude the pollution of the sacred elements: earth (), water (), and fire (), the bodies of the dead are placed at the top of towers and there exposed to the sun and to scavenging birds and necrophagous animals such as wild 	Tower of Silence
7756717	dogs. Thus, as an early-20th-century Secretary of the Bombay Parsi community explained: putrefaction with all its concomitant evils... is most effectually prevented." In current times. Structure and process. Modern-day towers, which are fairly uniform in their construction, have an almost flat roof, with the perimeter being slightly higher than the centre. The roof is divided into three concentric rings: the bodies of men are arranged around the outer ring, women in the second ring, and children in the innermost ring. The ritual precinct may be entered only by a special class of pallbearers, called , from the , consisting of  the word elements, ('caretaker') and ('pollutants'). Once the bones have been bleached by the sun and wind, which can take as long as a year, they are collected in an ossuary pit at the centre of the tower, where—assisted by lime—they gradually disintegrate, and the remaining material, along with rainwater run-off, seeps through multiple coal and sand filters before being eventually washed out to sea. Iran. In the Iranian Zoroastrian tradition, the towers were built atop hills or low mountains in locations distant from population centres. The Iranian Zoroastrians gradually discontinued their use and began to favour  burial or cremation. The decision to change the system was accelerated by two considerations: while the towers had been built away from population centres, the growth of the towns led to the towers now being within city limits. Furthermore, many of the Zoroastrians found the system outdated. Following long negotiations between the "anjuman" societies of Yazd, Kerman, and Tehran, the latter gained a majority and established a cemetery some 10 km from Tehran at Ghassr-e Firouzeh (Firouzeh's Palace). The graves were lined with rocks and plastered with cement to prevent direct contact with the earth. In Yazd and  Kerman, in addition to cemeteries, orthodox Zoroastrians continued to maintain a tower until the 1970s when ritual exposure was prohibited by law. India. Following the rapid expansion of the Indian cities, the squat buildings are today in or near population centres, but separated from the metropolitan bustle by gardens or forests. In Parsi Zoroastrian tradition, exposure of the dead is also considered to be an individual's final act of charity, providing the birds with what would otherwise be destroyed. In the late 20th century and early 21st century the vulture population on the Indian subcontinent declined (see Indian vulture  crisis) by over 97% as of 2008, primarily due to diclofenac poisoning of the birds following the introduction of that drug for livestock in the 1990s, until banned for cattle by the Government of India in 2006. The few surviving birds are often unable to fully consume the bodies. In 2001, Parsi communities in India were evaluating captive breeding of vultures and the use of "solar concentrators" (which are essentially large mirrors) to accelerate decomposition. Some have been forced to resort to burial, as the solar collectors work only in clear weather. Vultures used to dispose of a body in  minutes, and no other method has proved fully effective. The right to use the Towers of Silence is a much-debated issue among the Parsi community. The facilities are usually managed by the , the predominantly conservative local Zoroastrian associations. These usually having five priests on a nine-member board. In accordance with Indian statutes, these associations have domestic authority over trust properties and have the right to grant or restrict entry and use, with the result that the associations frequently prohibit the use by the offspring of a "mixed marriage", that is, where one parent is a Parsi and the  other is not. The towers remain in use as sacred locations for the Parsi community, though non-members may not enter them. In Mumbai visitors are shown a model of a tower. Organized tours can be taken to the site.