Natural Radioactivity in Soil (Bq.Kg-1)

Country	Type of Radioactive Isotope
	K-40	U-238	Ra-226	Th-232
India	400	29	29	64
China	440	33	32	41
Japan	310	29	33	28
USA	370	35	40	35
Russia	520	19	27	30
Spain	470	NA	32	33

Mean values are given from wide range of values

Courtesy: UNSCEAR, 2000

Natural Background Radiation in Various Cities of India

City	µGy.yr-1
	Cosmic	Terrestial	Total
Mumbai	280	204	484
Kolkata	280	530	810
Delhi	310	390	700
Chennai	280	510	790
Bangalore	440	385	825

As one shifts from Mumbai to Delhi, he is going to get 216 µGy additional natural radiation dose which is 10 times more than that from a nuclear power plant.