FIVE cities in the Netherlands are participating in an innovative experiment to usher in healthier environs. They are building public housing geared to safeguarding health and protecting the environment. In Amersfoort, for instance, over 4,000 such houses are being built.

A successful example of such environmentally correct housing is Ecolonia, a six-month-old, 101-house community near the Hague. The houses are made of brick, stone or wood and have such features as solar heating, ceramic sewage pipes and rainwater for toilets, gardening and car-washing.