Eco fashion is simply the fashion that is environment friendly. I read a precise definition of Eco fashion from About.com i.e. "clothes that take into account the environment, the health of consumers and the working condition of people in the fashion industry."
The first point is cloths that take into account the environment:
All clothes and accessories (like hand bags, jewellery, shoes) that are made up of organic cotton and recycled material like Paper and Plastic (recycled from soda bottles) are considered Eco friendly.
Secondly Health of consumer is involved:
Eco fashion do not include chemicals, bleaches, colors and dyes because these do harm human health.
Thirdly working condition of fashion industry workers:
This means that workers earn fair amount of salary from their work as well as work in a good Eco friendly environment where there is no danger of chemicals and harmful substances.
Designers have been using these Eco friendly materials for their products for many years but this term Eco fashion gained an edge in February 2005 when a team of non-profit people organized a fashion show in New York teaming up with Barney's, named "Future Fashion".At this event most famous designers showcased their Eco friendly fabric designs and outfits.
In the picture below is a girl wearing a dress made of recycled plastic.