However, air pollution remains a severe problem, especially in the industrialised north, reaching the tenth highest level worldwide of industrial carbon dioxide emissions in the 1990s.[80] Italy is the twelfth largest carbon dioxide producer.[81][82] Extensive traffic and congestion in the largest metropolitan areas continue to cause severe environmental and health issues, even if smog levels have decreased dramatically since the 1970s and 1980s, and the presence of smog is becoming an increasingly rarer phenomenon and levels of sulphur dioxide are decreasing.[83]
Many watercourses and coastal stretches have also been contaminated by industrial and agricultural activity, while because of rising water levels, Venice has been regularly flooded throughout recent years. Waste from industrial activity is not always disposed of by legal means and has led to permanent health effects on inhabitants of affected areas, as in the case of the Seveso disaster. The country has also operated several nuclear reactors between 1963 and 1990 but, after the Chernobyl disaster and a referendum on the issue the nuclear program was terminated, a decision that was overturned by the government in 2008, planning to build up to four nuclear power plants with French technology. This was in turn struck down by a referendum following the Fukushima nuclear accident.[84]
Deforestation, illegal building developments and poor land-management policies have led to significant erosion all over Italy's mountainous regions, leading to major ecological disasters like the 1963 Vajont Dam flood, the 1998 Sarno[85] and 2009 Messina mudslides