According to a statement released by Harvard University , Alexander More of Long Island University and the University of Maine and his colleagues compared climate data
collected from an ice core from a central European glacier with early twentieth-century historical records, and found that a six-year period of “miserable weather” preceded and overlapped with major battles of World War I and peaks in the numbers of deaths from the Spanish flu. “Basically, we saw a spike in cold, wet marine air from the northwest Atlantic that came down into Europe and lingered,” More said. Trench warfare in the cold, torrential rains and the resulting mud likely contributed to the run-down condition of soldiers’ health, in addition to malnutrition brought on by crop failures. The weather may have also disrupted the migratory patterns of disease-carrying waterfowl, More explained. The outbreak of the Spanish flu in the spring of 1918 is thought to have been connected to troop movements, infecting more than 500 million people and killing between 30 and 50 million.

In 1994, the UN General Assembly proclaimed 16 September the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing, in 1987, of the Montreal Protocol on Substances that Deplete the Ozone Layer (resolution 49/114).
The principal aim of the Montreal Protocol is to protect the ozone layer by taking measures to control total global production and consumption of substances that deplete it, with the ultimate objective of their elimination on the basis of developments in scientific knowledge and technological information.
The ozone layer, a fragile shield of gas, protects the Earth from the harmful portion of the rays of the sun, thus helping preserve life on the planet.
The phaseout of controlled uses of ozone depleting substances and the related reductions have not only helped protect the ozone layer for this and future generations, but have also contributed significantly to global efforts to address climate change; furthermore, it has protected human health and ecosystems by limiting the harmful ultraviolet radiation from reaching the Earth.

The United Nations’ (UN) International Day of Democracy is annually held on September 15 to raise public awareness about democracy. Various activities and events are held around the world to promote democracy on this date.
Background
The UN strives to achieve its goals of peace, human rights and development. It believes that human rights and the rule of law are best protected in democratic societies. The UN also recognizes a fundamental truth about democracy everywhere – that democracy is the product of a strong, active and vocal civil society.
The UN general assembly decided on November 8, 2007, to make September 15 as the annual date to observe the International Day of Democracy. The assembly invited people and organizations, both government and non-government, to commemorate the International Day of Democracy. It also called for all governments to strengthen their national programs devoted to promoting and consolidating democracy. The assembly encouraged regional and other intergovernmental organizations to share their experiences in promoting democracy.
The International Day of Democracy was first celebrated in 2008. The UN general assembly recognized that the year 2008 marked the 20th anniversary of the first International Conference of New or Restored Democracies, which gave people a chance to focus on promoting and consolidating democracy worldwide.

The Day aims to:
1. Raise public awareness at all levels—individual, community, corporate and government—that clean air is important for health, productivity, the economy and
the environment.
2. Demonstrate the close link of air quality to other environmental/ developmental challenges such as – most and foremost – climate change and the global Sustainable Development Goals.
3. Promote and facilitate solutions that improve air quality by sharing actionable
knowledge best practices, innovations, and success stories.
4. Bring together diverse international actors working on this topic to form a
strategic alliance to gain momentum for concerted national, regional and
international approaches for effective air quality management.
The United Nations General Assembly adopted the resolution to hold an International
Day of Clean Air for blue skies on December 19, 2019, during its 74th session and
invited the United Nations Environment Programme ( UNEP ) to facilitate the observance of the International Day, in collaboration with other relevant organizations. The Climate and Clean Air Coalition ( CCAC ) worked with UNEP and the Republic of Korea to advocate for the day in the lead up to the decision.

On 2 December 2009, the 64th session of the United Nations General Assembly declared 29 August the International Day against Nuclear Tests through the unanimous adoption of its resolution 64/35 . The Preamble of the resolution emphasizes that “every effort should be made to end nuclear tests in order to avert devastating and harmful effects on the lives and health of people” and that “the end of nuclear tests is one of the key means of achieving the goal of a nuclear-weapon-free world.”
The main mechanism for eradicating nuclear weapons testing is the Comprehensive
Nuclear-Test-Ban Treaty (CTBT) . It was adopted by the United Nations General
Assembly on 10 September 1996. To date, 184 countries have signed the treaty and 168 have ratified it. For the Treaty to enter into Force, it must be ratified by those States with significant nuclear capabilities.
While the general consensus within the international community is that nuclear weapons tests pose life-threatening risks, there still exists to some degree a lingering suspicion of the possibility of clandestine nuclear weapons testing. There is also a concern that if nuclear weapons cannot be tested their reliability may be in jeopardy. However, over the years, advances in science and technology have exponentially boosted the capacity to monitor and verify compliance mechanisms and nuclear weapons proliferation detection. These activities and tracking tools have been initiated and developed by the Provisional Technical Secretariat of the CTBT Organization (CTBTO) Preparatory Commission. Despite the stalled entry-into-force, an increasingly robust public advocacy, including activities and events undertaken on the International Day against Nuclear Tests, is exerting pressure on the powers-that-be to move forward on the ratification of the treaty with a view towards the ultimate eradication of nuclear weapons testing.
The Preparatory Commission of the CTBTO and its 168 ratifying States vigorously
continue to push for the Treaty’s entry into force. The CTBTO’s International Monitoring
System, already encompassing nearly 90 per cent of States, provides confidence that no nuclear explosion will escape detection.
However, nothing can play as crucial a role in avoiding a nuclear war or nuclear terrorist
threat as the total elimination of nuclear weapons. Bringing an irreversible end to nuclear explosions will prevent the further development of nuclear weapons.