^That's a 40 mm x 10 mm fan on top of the chipset heatsink. Some worthless chinese junk - mine conked off after a brief period of usage. You may substitute the defunct fan with a similar one or you can tie a slightly bigger one on top of it using cable ties to the heatsink which's what I did.
If you're looking for 40 mm x 10 mm ones, see if you can find a Sunon Maglev make. The fan may cost you around 300~350 INR but would last significantly longer and sadly, is a tad noisier but using PWM control, the fan speed could be controlled.