From midnight, diesel costs 99.50 denars per litre. Fifty deni below the three-digit mark. The Energy Regulatory Commission adopted a decision raising diesel by one denar, while both petrol grades fall by two denars each - EUROSUPER BS-95 is now 91 denars, and EUROSUPER BS-98 is 93 denars.

Formally, the average price of petroleum products is down 1.24 percent compared with the decision of 27 July. Formally, then, fuel is cheaper. In practice, for anyone driving diesel - and that is most of the freight and agricultural fleet in this country - the bill is once again higher.

Why petrol falls while diesel climbs

Reference prices on the world market diverged: petrol fell by 2.069 percent, while diesel jumped by 4.806 percent. The denar-to-dollar exchange rate rose by 0.1423 percent. The regulator applied a reduced excise of 2 denars per litre for petrol and 4 denars per litre for eurodiesel - without those excise cuts the price at the pump today would look rather different.

Extra-light heating oil for households is now 98.50 denars per litre, an increase of 50 deni. Mazut M-1 NS is 46.419 denars per kilogram, cheaper by 1.68 denars.

The psychological threshold and the real one

A lot will be written about what happens when diesel crosses the 100-denar mark. That makes a good headline and poor economics. The difference between 99.50 and 100.50 denars is one denar. The difference between diesel a year ago and diesel today is the one that is actually felt - in the costs of a haulier, of a bakery distributing bread, of a farmer driving a tractor out to the field.

Every diesel increase travels down the entire chain and finally stops at the consumer, because transport is a cost every business passes on. Petrol falling by two denars is good news for drivers of passenger cars. Diesel rising by one denar is good news for nobody - it goes into the price of everything that gets transported.

The new prices apply from 5 August. In two weeks the regulator does the maths again.