Twenty female students became intoxicated after inhaling gas in a school in Tabriz, in the northwest of the country.
This was announced by the Irna agency, announcing that the students were taken to hospital for respiratory problems after inhaling the gas at school, during the second day of lessons after a two-week break for the beginning of the Iranian new year.
Similar episodes have been happening since November, the first were reported in the city of Qom and more than 5,000 female students became intoxicated after inhaling gas in 230 different schools in 26 provinces of the country.
Only yesterday, five female students of the 22-Bahman girls' school in Naghadeh, in the province of West Azerbaijan in the north-west of the country, were hospitalized after inhaling toxic gas while at school.
ANSA agency
Iran: no education for unveiled female students - Middle East
Announcement by the Ministries of Education and Health, mandatory to abide by the dress code of schools (ANSA)
The authorities have not yet identified those responsible for the poisonings and for this reason they have been harshly criticized by the population.
According to activists, the poisonings are a revenge of the Tehran government against the female students due to their participation in the protests that erupted after the death of Mahsa Amini, the 22-year-old of Kurdish origin who lost her life in late September after being taken into custody by the moral police because she did not wear the veil correctly.