Why Kerala has banned oleander flowers in temple offerings?

Kerala government-controlled temple boards have recently banned use of oleander flowers (locally arali) in temple offerings.

About the Oleander:

• Oleander is a drought-tolerant plant cultivated worldwide in tropical, subtropical, and temperate regions. Different varieties of oleander have unique flowers with varying colors.
• It is also known by its aliases: Nerium oleander, rosebay, arali, and kanaveeram.
• All parts of the plant are highly toxic due to the presence of cardiac glycosides, including oleandrin, folinerin, digitoxigenin, nerioside, and oleandroside.
• The effects of oleander toxicity can range from nausea, diarrhea, vomiting, and rashes to confusion, dizziness, irregular heartbeat, slow heartbeat, and even death.

Ref: Source