In this paper the 200 mb flow regimes during a drought year (1972) are contrasted with those during a normal rainfall year (1967) over the global tropics for the northern summer months. It is shown that the deficient rainfall over central India and western Africa during 1972 may be related to the following: (i) warm sea-surface temperatures over the equatorial Pacific; (ii) an excessive number of typhoon days over the equatorial Pacific; (iii) strong east-northeasterlies over the equatorial eastern Indian Ocean (related to upper-level outflows from the typhoons); (iv) a weaker tropical easterly jet; (v) a weaker meridional pressure gradient over India; (vi) a weaker Tibetan High; (vii) a south-eastward shift over the major circulation patterns as well as of several dynamical parameters; (viii) a weaker vertical wind shear and a weaker measure of the combined barotropicbaroclinic instability over west Africa; and (ix) weaker westward steering for rain-producing disturbances over India and a consequent stronger influence of the mountains. A sequential interrelationship of the above aspects of the drought problem are discussed in this paper. Introduction The monsoonal rainfall over south Asia and west Africa undergoes interannual variations. Although some of the anomalous periods have more of a regional character, i.e., a period of drought over parts of a continent may not occur at the same period in other regions, there do exist periods of widespread drought that extend from west Africa to India. Such droughts occurred during the summers of 1877, 1899, 1918 and 1972.