Toxic haze that settled over much of China during the last three weeks has triggered a flight reflex among residents, leading to the rising popularity of smog avoidance travel packages to far-flung locations such as Iceland and Antarctica.

Traveler's online keyword searches for terms such as "smog escape," "lung cleansing" and "forests" had tripled amid the air pollution, according to a report titled "Smog Escape Travel Ranking" from International Ltd. last month. Smog avoidance tourism has become a major theme for winter travel this year, with the Seychelles, Maldives and Iceland touted as getaways with the freshest air, according to the online travel service.

Heavy smog has forced 62 cities including Beijing to issue health alerts since Jan. 1, and hundreds of flights have been canceled or delayed. More than half of China's cities suffered medium to severe pollution on Jan. 3 during the latest wave, with PM2.5 — the tiny particles that pose the greatest risk to health — as the main pollutant in most of them, according to the government.