Riding a bike does not cause pollution.
Pollutants can be released either as gases or as particles.
Riding a bike does not release particles.
What does not release particles?
(a) riding a bike
(b) driving a car
(c) influenza
(d) monotremes
(e) creating smog
(f) burning coal
(g) It remains dormant
(h) peachleaf willow