I think you need to review your usage a bit here. Downloading files (any) can push your systems temp & fans quite hard. You could try using an external HD to hold your downloads as you download them as well as CD/DVD burner to lessen the heat buildup within your system as a start.
You should also think about using your system in a cooler environment if you can. Try the night or a room with AC. While that may not be possible you may need to lessen the amount of downloading you do during the heat of the day.
Download a good temperature & fan monitoring app. I like this one: Temperature Gauge Pro. Review the temp modeling they have for your system (you'll need the full version). So you can monitor things better.
You may need to do some cleaning of dust buildup internally and refresh the thermal paste on the CPU/GPU heat sink. Given the area you live in if its dusty this may need to be done more often.
As you didn't give us an exact model I can't offer you much more here.
If you believe your system is running hot without any heavy loading as I suggested, you should open up your system and clean out the dust buildup. Use a soft paint brush to scrub the surfaces and can'ed air to blow away the debris. Don't spin up the fan with the can'ed air as you can damage it. And lastly, don't snag any of the components in the process.
You can follow also this IFIXIT guide: MacBook Pro 13" Unibody Mid 2009 Logic Board Replacement to take the logic board out to refresh the thermal paste. I strongly recommend you use a good quality paste like: Arctic Silver Thermal Paste and use this cleaner to clean the old paste fully off: Arctic Silver ArctiClean as many of these pastes are hard to clean off. Follow this technique guide on how to effectively put down the new paste: Technique: Applying Thermal Paste.