Sustainable Development Goal (SDG) 3 focuses on ensuring healthy lives and promoting well-being for all at all ages. It has several targets aimed at addressing various health challenges. Target 3.9 of SDG 3 specifically states:
"By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination."
Let's briefly look at why the other options correspond to different targets within SDG 3 or other SDGs:
(1) Strengthen the implementation of the World Health Organization framework convention on Tobacco control in all countries as appropriate: This corresponds to Target 3.a of SDG 3.
(2) Strengthen the capacity of all countries, in particular developing countries, for early warning, risk reduction and management of national and global health risks: This corresponds to Target 3.d of SDG 3.
(4) By 2030, reduce by one third premature mortality from non-communicable diseases through prevention and treatment and mental health and well-being.: This corresponds to Target 3.4 of SDG 3.
Therefore, the \(9^{th}\) target (Target 3.9) of Sustainable Development Goal 3 is to substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water, and soil pollution and contamination by 2030.