Details of the leaked measures are to be revealed soon, but reports say the existing limit of up to 130km/h would still be permitted at night.
The new limit is set to come in during 2020, public broadcaster NOS reports.
The crisis is so severe that big infrastructure projects have been put on hold. A ruling in May by the top court in the Netherlands on nitrogen oxide emissions affected thousands of plans for roads, housing and airports.
The government wants to build 75,000 homes next year, so for the past week the cabinet has tried to find a solution to cutting the pollutants. Among the options discussed was a ban on vehicles on Sunday.
Under the proposals, drivers would be allowed to revert to the current maximum between 19:00 and 06:00.
Bringing the motorway speed limit down to 100km/h would make the Netherlands the lowest in Europe, on a par with Cyprus which has far fewer motorways.
The most common maximum speed limit in Europe is 130km/h while in the UK it is 112 km/h.
Last month, farmers reacted angrily to claims that intensive farming was partly to blame for the emissions problem, after a report called for drastic measures to reduce livestock as well as action on the roads.