A fine-dust warning was issued for the Seoul metropolitan area and central parts of the country on Tuesday as smog stagnated over the peninsula.The warning is issued when the average PM10 fine particle concentration exceeds 150 ㎍/㎥ per day, cutting working hours for factories that generate lots of emissions. The Korea Meteorological Administration on Monday said that stagnant air has caused ultrafine particles generated at home and abroad to accumulate over the peninsula. But the thick haze will dissipate gradually from Wednesday afternoon as winds rise. Warm spring weather is expected this week, with daytime highs above 10 degrees Celsius in most part of the country, two to five degrees higher than the seasonal average. Tuesday morning was still chilly at -3 and 6 degrees across the country, but daytime highs will reach 5 to 15 degrees.Rain is expected from Thursday in southern parts, but the KMA said it remains to be seen whether it will be enough to alleviate the drought.