Formula manufacturing is environmentally (as well as
economically) costly:
the main ingredient in most formula is cow's milk, and cow
excretion and flatulence are responsible for 1/3 of the world's
methane emissions.
Formula packaging consumes several million tons of tin,
glass, and paper every year.
Formula transportation contributes to pollution too.
Formula feeding equipment (bottles, teats, etc.) is mostly
plastic and not very durable. Manufacturing and disposal of
such equipment is environmentally costly.
Sterilizing feeding equipment and heating formula consumes
energy.
Breastmilk is environmentally perfect:
no pollution is created in its making.
No delivery costs--it's available right at the source.
No cleaning and sterilization problem--it's always
clean.