Maximum Allowable Inputs (MAI) of nutrients are a part of the HELCOM nutrient reduction scheme, indicating the maximal level of total (water- and air born) input of nitrogen and phosphorus to the Baltic Sea sub-basins (marine background information layer of the HELCOM map service) that is allowed to fulfil the targets for the sea unaffected by eutrophication. The targets were first included into the Baltic Sea Action Plan in 2007 and then updated in the Copenhagen Ministerial Declaration in 2013.

The assessment of progress towards MAI of nitrogen and phosphorus is based on data on normalized average total input to the sub-basins of the Baltic Sea during 2010-2012. The fulfilment of MAI is identified by comparing the total input to a particular sub-basin with the Maximum Allowable Input for that sub-basin. The progress achieved by 2012 is given in percentages of MAI where values below 100% indicate fulfilling the requirements of the HELCOM nutrient reduction scheme.

The MAI of nitrogen and phosphorus were fulfilled in Kattegat, the Danish Straits and Bothnian Sea during 2010-2012 (see Table below). For Bothnian Bay nitrogen inputs are close to MAI but cannot be regarded as fulfilled with statistical certainty. Total normalized nitrogen and phosphorus inputs to the Baltic Sea have decreased by 9% and 14%, respectively, since the reference period (1997-2013) and 18% and 23% since the mid-1990s.

Table. Progress towards maximum allowable annual inputs of nitrogen and phosphorus achieved in 2010-2012 and the remaining reduction needed to reach MAI. Colours in the classification column are as follows: green=MAI fulfilled, yellow= not determined due to statistical uncertainty, and red=MAI not fulfilled. (Units in columns 2-4: tonnes per year).

The detailed description of the indicator including data on air- and water born input as well as long term trends of inputs since the mid-1990s is given in the relevant section of the HELCOM core indicators web page and specifically the
Core pressure indicator on nutrient inputs (MAI follow up).