The incident occurred at the building at 131 E. 21st Street just before 8:45 p.m.
Police say the child was playing with the side panels of an air conditioning unit when he pushed on it, falling out of a window.
The child was transported to Maimonides Medical Center where he's listed as stable.
The investigation is ongoing.
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Video shows 95-year-old grandmother assaulted by home aide in Harlem
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