Estimates put the amount of junk mail delivered to households in Hammersmith & Fulham, Lambeth, Wandsworth and the Royal Borough of Kensington and Chelsea, at 7.4 million pieces a week.
Recycle Western Riversides Reclaim your doorstep campaign aims to teach residents how to reduce this paper mountain.
Campaign manager Sam Jarvis said: An easy way for people to reduce their household waste is to say no to junk mail. Its frightening to think that over three million trees are used each year to produce junk mail, most of which ends up in the bin. Its time we all took a stand against this wasteful practice.
A campaign roadshow is taking the message to shopping centres across the boroughs and so far 450 residents have pledged to say no to junk mail by following the campaigns five steps: signing up to the mailing preference service at www.mpsonline.org.uk, stopping unaddressed mail received from Royal Mail by emailing email@example.com, sticking no junk mail stickers to letterboxes, attaching return to sender or not at this address stickers to wrongly addressed mail, and ticking the opt-out box for marketing found on electoral registration forms and when signing up for new products and services.