UPSC CAPF AC 2019 Paper

Doldrums, also called equatorial calms, equatorial regions of light ocean currents and winds within the intertropical convergence zone (ITCZ), a belt of converging winds and rising air encircling Earth near the Equator. Doldrum is the equatorial belt of low atmospheric pressure where the NE and SE trade winds converge on, and meet each other , producing calm and light surface winds and a strong upward movement of air.
The doldrums are variable both in position and extent, usually moving northward and southward with the sun; their movement, however, is much less than that of the sun, being about 5 degrees on each side of the mean position of equator, with a lag of one or two months behind the sun.