Hitoshi Tamura makes sure the curry restaurants he operates in Tomakomai, a city in Hokkaido, take all the necessary precautions against COVID-19.

Those who enter are asked to wear masks, disinfect their hands and measure their temperatures. Transparent plastic panels stand between cashiers and customers to block any pathogen-laced droplets produced by coughing and sneezing. Guests are given numbered tags and asked to pick up their orders so they don’t need to flag down servers.

But the dry and often freezing climate of the winter months is proving to be challenging as restaurants, shops and other facilities scramble to keep their premises sufficiently ventilated, a vital measure in reducing the risk of indoor transmission as new coronavirus cases soar to record highs.