Beijing and environs will be smothered in a haze of filth again this week, as level-5 air pollution makes an unwelcome Spring return to the Chinese capital.

Air Quality Index (AQI) readings could hit 300 in Beijing, Tianjin and Hebei Province on Thursday and Friday, according to the Beijing Municipal Environment Monitoring Center.

As temperatures rise, dispersal of foul air becomes more difficult. Parts of north China have been smogbound since the start of this week. Beijing made it to level-5 on Wednesday morning, the center said.

The situation will improve on Saturday and the smog should be gone by next Tuesday, according to the center forecast.