QUETTA (APP) - Pakistan International Airlines (PIA) has cancelled operation of all its Quetta-bound flights on the second consecutive day on Sunday due to dusty weather and poor visibility in the provincial capital, PIA officials told to this news agency. They said that the flights which had been cancelled as follows: PK-363 Islamabad-Quetta-Karachi, PK-352 Karachi-Quetta-Islamabad, PK-323 Lahore-Quetta, PK-231 Quetta-Dubai, PK-232 Dubai-Quetta, PK-322 Lahore-Quetta, PK-523 Gawadar-Quetta, and PK-524 Quetta-Turbat. Besides, operations of Quetta-bound flights of other private airlines were also cancelled. Extreme dust enveloped the entire city and its surroundings which also caused difficulties for traffic movement and pedestrians in the valley. The cancellation of flights caused great inconvenience for the passengers who could not travel to their respective destinations. The dusty weather has also caused increase in skin, sore throat and other allergic diseases. Dermatologists have suggested the people to avoid and restrict their unnecessary movements due to dusty weather as it causes increase of allergic diseases.     The PIA officials said that operation of flights would also be cancelled on Monday, if the dusty weather continued to prevail in the city and its suburban areas. The Regional Met Office has forecast that dust-storm and partly cloudy weather would continue to prevail in the valley and its surrounding areas during the next 24 hours.