Marina Varlamova, a student from the US, was puzzled by her flat's thick curtains when she came to Hong Kong to study light pollution.
She soon figured out their purpose. Used to resting in a pitch-black environment, she and her three companions could hardly sleep because of bright lights outside their Sham Shui Po home.
In a survey by the four students from Worcester Polytechnic Institute in Massachusetts, 13 per cent of respondents had considered moving because of lighting outside their homes. Of the 341 people interviewed, 68 per cent wanted lighting in their neighbourhood reduced.
Spotlights were blamed for causing the most disturbance - they were given the highest rating, 4.15 out of six, as the perceived source of light pollution. Flashing signs followed with 4.12 points.
Respondents reported a medium level of visual fatigue and weariness caused by the lights.
To get a sense of how brightly the city is lit, the students took a photometer to the busiest districts.
While British agencies recommend that lighting have an intensity of 60 to 100 lux from a distance of 30.5 metres, the four found light from a building in Causeway Bay with various neon signs on its lower floors was as bright as 176 lux.