Also found at Anthroforum, thanks to Ayepod, and sourced to Scientific American.
It seems that Michael Petraglia, who already surprised us some years ago with his discovery of pre- and post-Toba continuity at Jawalpuram, has now come to find that microliths are found in the subcontinent dating to c. 38,000 years ago.
South Asian microliths (below) compared with older tools (above). Each segment of the scale is 1 cm.
This may be one of the oldest worldwide dates for this curious technological phenomenon of blade reduction on Earth and may help to explain, maybe, the spread of Y-DNA macrohaplogroup P and its derived lineages R and Q, whose origins seem to be in the subcontinent.
Update: I have located the original paper and another divulgative article on it. Apparently Petraglia argues for 35-30,000 years ago (though these may be uncalibrated BP - unsure).
M. petraglia et al. Population increase and environmental deterioration correspond with microlithic innovations in South Asia ca. 35,000 years ago. PNAS 2009 (behind paywall by the moment).
And also check this article at New Scientist.