Air Pollution Control Act Article 46

Those in-use motor vehicles for which air pollutant emissions are determined through visual determination, visual inspection or remote sensing performed by special municipality, county or city competent authority inspection personnel, which fail to meet the emission standards in Article 36 (2) or the remote sensing screening standards officially announced by the central competent authority, shall be repaired and undergo testing at a designated location by the deadline designated in the notification sent by the special municipality, county or city competent authority.Citizens may report the air pollutant emissions of in-use motor vehicles to competent authorities at all levels. Those vehicles which have been reported and notified by competent authorities at any level shall undergo testing at a designated location by a designated deadline.
中文原文 空氣污染防制法第46條
使用中之汽車排放空氣污染物,經直轄市、縣(市)主管機關之檢查人員目測、目視或遙測不符合第三十六條第二項所定排放標準或中央主管機關公告之遙測篩選標準者,應於直轄市、縣(市)主管機關通知之期限內修復,並至指定地點接受檢驗。
人民得向各級主管機關檢舉使用中汽車排放空氣污染物情形,被檢舉之車輛經各級主管機關通知者,應於指定期限內至指定地點接受檢驗。

English translation for reference only; the Chinese text prevails. Not legal advice.