Almost 120 flights have been warned and two have been canceled since the launch in June of a campaign to reduce delays at Beijing Capital International Airport.

Organized by the Civil Aviation Administration of China (CAAC), the campaign produces a list every 10 days of the 20 most-delayed flights.

All those that appear on the list are given a warning, and if they appear twice they are canceled.

The campaign aims to prevent large-scale flight delays next August when Beijing hosts the 2008 Olympic Games, the CAAC said in a news release on its website on August 2.

To date, nearly 120 flights have been given warnings, while Air China and China Eastern have each had a flight canceled.

The CAAC has also cut the number of daily flights from the airport by 92, the release said.

An unnamed CAAC official was quoted by the news release as saying the measure will free-up airspace and therefore reduce delays.

Eighteen of the country's airports, including Beijing, Shanghai Hongqiao, Chengdu, Shenzhen, Dalian and Urumqi, are currently operating at maximum capacity, the CAAC said.

In Beijing, airspace is particularly limited, with the gaps between flights during peak times being less than a minute.

Also, during July and August, thunderstorms, hailstorms and gale-force winds are common, which can cause further delays.

According to the CAAC, thunderstorms have this week alone delayed some 10,000 passengers traveling through Beijing Capital International Airport. On July 31, four flights were delayed for 10 hours or more.