a.
The environmental qualities of the two rivers vary, to some extent.
Both of the rivers start in the centre of Europe. The Rhine flows west through France, Germany and the Netherlands towards the North Sea, while the Danube flows east through seventeen countries to the Black Sea. The river Rhine flows through a rift valley, a gorge and a wide plain as it makes its way to the sea. The Danube basin includes such diverse areas as the Alps, the Pusta and the Delta.

The Rhine and the Danube are both very busy rivers. Ocean-going vessels, container ships and barges sail on both rivers. Over one million containers are carried along the length of the Rhine each year, and when the Danube was closed to shipping because of bombing the cost was estimated at $5 million a day. Both rivers have undergone many changes to allow ships to travel their length, such as the building of dams, canals and removal of meanders. Both rivers have been polluted - the Rhine as a result of accidents and spills, and the Danube as a result of bombing during the Balkan conflict - and their plant and animal life has suffered.

Both the Rhine and the Danube rivers flow through highly industrialised areas and both rivers have suffered from pollution as a result. In the 1970s, factories had dumped so many toxic chemicals and waste products in the Rhine that its water was not safe for drinking. Factories also dumped waste in the Danube, and the impact of pollution on the Danube was especially high as previous governments invested in industry rather than the environment. Authorities on both rivers have brought in legislation to ban dumping toxic waste and prevent industrial pollution. This has improved water quality, particularly in the Rhine.

80 million people depend on the Danube and 50 million people depend on the Rhine. In both cases, the flood plains have been developed to meet the need for more housing. In times of flooding these areas can be covered with river water, resulting in damage to property. People along both rivers also create pollution - even though they depend on the river for drinking water. As a result, expensive treatment plants have had to be built in order to deal with the pollution along the Rhine. However, few Danube countries can afford to build the plants they need and most end up dumping their waste in the river untreated.

b.
The effectiveness of local, national or international policies varies because of the effectiveness of the bodies sponsoring them and the length of time they have been in place.

Both rivers are controlled by various agreements. Countries along both rivers have come together to form Commissions which pass legislation aiming to reduce pollution and improve water quality. The Convention for the Protection of the Rhine against Chemical Pollution was the first effective piece of legislation aimed at reducing the pollution levels in the Rhine. The Rhine Action programme of 1987 was developed in order to improve the quality of the river and the Rhine 2020 programme builds on it. The Danube River Protection Convention was drawn up in 1994. The aim of the Danube Pollution Reduction Programme is to improve water quality in all the water bodies in the Danube basin - the tributaries as well as the main river.

The strategies used to clean up the Rhine have been very successful. The Convention for the Protection of the Rhine against Chemical Pollution resulted in a drop in the levels of chemical pollution in the Rhine, and oxygen levels rose accordingly. The Rhine Action Programme has also been very successful - the concentration of nitrates and phosphates dropped by half, and some other types of pollution have been reduced by 80% to 100%. The strategies used for the Danube have had varying degrees of success. The Belgrade Convention works to maintain and improve the navigation channel so it's in a good position to suggest that these works be planned and carried out in an environmentally aware way. On the other hand, the Danube Pollution Reduction Programme is still in its infancy so it's difficult to assess how successful it will be in reducing pollution right across the Danube basin.