White foam, thick and voluminous, was pouring from the Lepenec river into the Vardar, in the Karposh municipality area. That pronounced white colour and that volume are usually a sign of synthetic pollution. Inspectors went out to the site, flew a drone to find the culprit, and took samples. A day later the water looks clear, and there are no results.

The report reached the 112 system at 2.30pm, confirmed Muhamed Ali, director of the Crisis Management Centre. The Skopje regional crisis management centre immediately notified the City of Skopje's municipal inspectorate and sent photographs from the location. Representatives of the State Environmental Inspectorate also went to the site.

Skopje Mayor Orce Gjorgjievski said the city's inspection services went out immediately, that the Environment Ministry's services were also contacted, that a drone was flown to detect the source, and that teams from the public water and sewage utility took river samples for analysis. "I believe the source will be identified before long," he said.

The response, then, was fast and coordinated. That should be said. But a fast response to the consequence is not the same as preventing the cause, and this is exactly where the story stops every time. The foam arrives, the institutions arrive, the drone flies, the samples are taken - and then the river cleans itself, because water flows, and the evidence flows away with it.

The opposition SDSM immediately linked the case to the water crises in other towns and called it an indicator of a systemic collapse of institutions. The political exploitation of an environmental incident is predictable and it does not substitute for analysis. What will substitute for it is a concrete finding: what the substance was, which outflow it came from, and who is going to be penalised.

Until then we have a familiar pattern. The pollution is visible, the response is visible, the accountability is not. The Lepenec basin is not an anonymous stretch - it is part of the city where, according to those who monitor it, occurrences like this are not unusual. If it has become routine, then identifying the polluter should have become routine too.

The question for next week is simple and worth repeating until it gets an answer: what did the samples show? If no answer comes, the next white foam will be met by the same drones and the same silence.