There is no detailed scientific investigation into whether there is a direct link between the 2015-2016 El Nino and Chennai city flooding yet.
Southern India could continue to experience higher than normal rainfall and this could cause further flooding due to El Nino, a phenomena which sparks global weather extremes, according to a UN report.
The ongoing El Nino weather pattern in the Asia and Pacific is likely to be one of the strongest since 1998 and will continue into early 2016, according to the advisory, which asks regional cooperation for early warning, in-season mitigation and long-term adaptation strategies to curb climate risk.
"The impact of the 2015-2016 El Nino could be even more severe in certain locations, such as the uplands of Cambodia, central and southern India, eastern Indonesia, the central and southern Philippines, central and northeast Thailand," said the Third Advisory Note on El Nino issued jointly by the UN Economic and Social Commission for Asia and the Pacific and the Regional Integrated Multi-Hazard Early Warning System for Africa and Asia (RIMES).
While many southeast Asian countries, particularly India and Sri Lanka, expect to face severe flooding caused by heavy rainfalls, some Pacific islands - Papua New Guinea, Timor-Leste, and Vanuatu, among others - have been experiencing a serious drought, causing water shortage and food insecurity, according to the report.
The 2015-2016 El Nino is likely to be one of the strongest El Nino events since 1997-1998.
Sri Lanka and southern India could continue to experience higher than normal rainfall and this could cause further flooding, particularly urban flooding, in certain locations, the report said.
In India, Chennai was hit exceptionally hard, with numerous deaths recorded due to severe flooding.
Up to 21.7 inches of rain was recorded, which drenched Tamil Nadu and over 7.9 inches fell in large areas of southeastern India and northern Sri Lanka.
Record-setting rainfall since November 2015 has generated severe floods resulting in the death of a large number of people, the report said.
"While there is no detailed scientific investigation into whether there is a direct link between the 2015-2016 El Nino and Chennai city flooding yet, the consensus that strong El Nino conditions has led to abnormal rainfall during the northeast monsoon season in South Asia indicates that El Nino had a part to play in the sequence of extreme weather events in India," the advisory said.
In the 2016 outlook, the advisory said that higher than normal rainfall is likely to continue over the southern India and South Asia, including the Maldives and Sri Lanka, during the winter period of December 2015 to February 2016.
Noting that the current UN climate change conference in Paris has discussed and addressed the impacts brought by El Nino, and that actions are being taken in some countries, the publication provided key guidance in this regard.
Regional cooperation, the note stressed, is of great importance, given the transboundary nature of El Nino risks.
Early warning and monitoring, pre or in-season mitigation, adaptation and response, as well as long-term risk management should be considered to tackle some shared vulnerabilities and risks.
"Only by coming together in the spirit of cooperation can the Asia-Pacific region hope to become truly disaster resilient and achieve sustainable development in the future," said the guidance.