Dozens of people scattered to take refuge as black smoke billowed through the Philips Stadion.
Dozens of people scattered to take refuge as black smoke billowed through the Philips Stadion, forcing the referee to suspend play five minutes into the second half.
Ten fans, four security guards and a steward suffered respiratory or eye problems, according to the Dutch press agency ANP. A 35-year-old man was arrested on suspicion of letting off the devices, it added.
The game resumed shortly after the interruption but photos and videos of the huge cloud of smoke, spewing out from behind advertising hoardings near the touchline, were shared widely on social media.
Players from both teams stood on the pitch watching the smoke cloud after referee Kevin Blom brought the game to a halt.
Jurgen Locadia scored the only goal after 25 minutes as defending Eredivisie champions PSV won 1-0, dealing a blow to 33-time winners Ajax who are bidding for their first title since 2014.
Peter Bosz's side could not afford to slip up after leaders Feyenoord's 2-0 win over Vitesse earlier on Sunday.
Ajax are four points behind Feyenoord with two games to play. PSV are third, a further three points behind.