Some problems aren’t apparent until you ask
From: MIT Technology Review - Sep/Oct 2013
35 Innovators under 35 - 2013

Amos Winter created a wheelchair specially tuned to the needs of people in
poor countries: sturdy enough for uneven terrain, nimble enough to negotiate
the indoors.

Read the entire article at:
http://www.technologyreview.com/lists/innovators-under-35/2013/humanitarian/amos-winter/

Links:
Amos Winter
http://web.mit.edu/awinter/www/
http://meche.mit.edu/people/index.html?id=683

Amos Winter: The cheap all-terrain wheelchair (video 11:14)
http://www.ted.com/talks/amos_winter_the_cheap_all_terrain_wheelchair.html

Wijit wheelchair
http://www.wijit.com/