824 India. 
latitude 20 degrees N., and still more along the coast 
of Lower Burma, and to a lesser extent also the delta 
of the Ganges and the southern slopes of the Himalayas. 
A moderately humid climate, if gauged by annual 
rainfall, prevails over the plateau occupying the larger 
part of the peninsula and the lower Ganges valley, 
while a rainfall of less than 15 inches occurs over the 
arid regions of the lower Indus. 
The rainfall, so unevenly distributed territorially, 
is moreover as unevenly distributed through the year. 
In most districts the principal rains are experienced 
in summer, the rainy season being followed by a long 
dry season. But on the Eastern coast the summer 
rains are slight, and the principal rainy season is 
delayed into October and November, while in Northern 
India and the Himalayas also winter rains occur, 
irregular and of short duration. 
Even where a relatively large rainfall prevails, the 
climate is dry on account of the high temperature, 
hence some 30,000,000 acres of the cultivated acreage 
(which comprises 225,000,000 acres in all) depend on 
irrigation, over half of this irrigated area lying in the 
tropical zone. : 
Roughly speaking, at least four climatic zones with 
many sub-types, may be recognized: the truly tropic, 
intensely hot and wet (over 75 inch rainfall), prevailing 
on the plains and tablelands of the lower half of the 
peninsula; the hot and dry (below 15 inch rainfall) 
climate of the Northwestern Indus plain and plateau; 
the moderately warm and dry to humid (30-75 inch 
rainfall) climate of the Ganges plain and central 
plateau; and the temperate to alpine, humid climate 
