257. As vas indicated in chapter rrf, the nuclear po'rers have perforned in allmore than 1,200 nucrear tests. fn the absence of officialry 6iien numbers, thefigures quoted in tabLe 5 are estinates based. on the data u..r"ifubI.. As seen fronthe tab1e" the najority of tests have been and sti11 are cond.ucted by the unitedStates and the USSR. fn recent years, an average of 30 to l+O tests iave beencarried out annua11y. Ifearly al1 of them are underground. t€sts, as nucleartesting in other envirorur.ent s is forbidd.en by the pa'tial test-ban Treaty of 1!dl,r'rhich has been adhered to by the united statls, the ussR end the united Kingdom.The two other nuclear-veapon States, !'rance ani. China, are not parties to theTreaty. China is sti1l conducting atnospheric tests, r,rhereas France dec1ared. in1971+ that it would abandon testing in th-e atroosphere. ltrearl-y af1 tests are carriedout at.special test sitesr sone of them outside the territory of the testingState (see map in figure XII). tL/35 /392 Annex Page 90 Natlon United States of Anerica USSR United Kingdom France uhana fnd.ia TotalTA3I,E 5. INOWN AND ?RESIIMED NUCLEAR EXPLOSIONS UP TO 31 D3CN,{BER ]979 A = Atmospheric U = Underground. Total U A I6L 2TLo.iu-Ly -Lyr+ )-lr Aueust 1953 U l.7O a/ 3 2 l+, -^/^) AUglfST ryoJ- J,L lecemoer _Ly I y 303 163 84,1 2I 0362 362 193 262 252 161 7721 37 T8 45 \252r\72 66j 265 \26 930 )+r 86 )1 25 110L1 379119 \986z 6tz73j 441792 r 233 Sources :SIPRI Yearbook f9d0 Zander and Araskog: Nuclear explosions, l9\r-L97?. Basic Data. foA )+ Report A \505-A1' Research Institute of National Defense, Stockholm' Aprif 1973' vith later amendroents. a/ Sorne of these may have taken place aft et 5 August 1963.A/35/92 English Annex Page 91 258. The main direct harm to the world population from nuclear-weapon testsderives from the l,rorld -!ri d.e dislersion cf rad.ioactive natter occurrina inparticular after atmospherie tests. The source of the radioactivity, vhich doesnot differ from that generated by nuclear explosions in a r,rar, is the fissionproducts, as I,re1l as many other nuclides produeed. at the tine of explosion in thenucl-ear device itselfr in other structural materials and in the close sugound.inegof the explosion point. After the debris reaches ground level and enters thebiosphere there are different pathnays for the individual rad.io-nuclides t,odel,iver radiati.on to mart. 259. The United Nations Scientific Connittee on the Effects of Atornic Radiationcontinuously estimates the doses that have been delivered. aI1d r,ril1 be delivered.
**Analysis**
The text appears to be discussing the effects of nuclear weapon tests on the environment and human health, specifically the release of radioactive materials into the atmosphere and the subsequent impact on the world population. The text also mentions the partial test-ban treaty and the number of nuclear tests conducted by various countries.

**Category**
Natural resources and environment, Health