asked the Under-Secretary of State for Air what explanations his experts in the Meteorological Office have advanced for the inordinate amount of fog suffered by the country during recent months.

Mr. Ward:

Fogs occur in calm and cloudless conditions associated with persistent anticyclones. These have been unusually frequent this winter.

Since fog has now become a major weapon of killing can we be assured by my hon. Friend that his experts are now in close touch with the Ministry of Fuel and Power as to the extent to which fog is caused by the unwelcome and undue amount of soot and smoke coming from the chimneys in our large cities?

Mr. Ward:

Fog itself is not caused by smoke; it is only polluted by smoke.