Midges are tiny dark grey flies, only about 2mm long with hair-fringed wings, most prevalent in spring and summer near sewage works. Also known as Filter Flies or Owl Midges, their grubs perform a useful purpose because they break down organic material at sewage works.
Should adults fly indoors, use a fly killer aerosol.
For a heavy infestation, we would recommend you contact professional pest control company, preferably a member of the IPCA to administer a professional treatment to solve the problem. A trained professional will have the technical knowledge and access to a range of professional use products and equipment which are not available to the public.