One verse

Bhagavad Gita 1.42

1.42

सङ्करो नरकायैव कुलघ्नानां कुलस्य च | पतन्ति पितरो ह्येषां लुप्तपिण्डोदकक्रियाः ||१-४२||

saṅkaro narakāyaiva kulaghnānāṃ kulasya ca . patanti pitaro hyeṣāṃ luptapiṇḍodakakriyāḥ ||1-42||

narakāya
make for hellish life
eva
certainly
kula-ghnānām
for those who are killers of the family
kulasya
for the family
ca
also
patanti
fall down
pitaraḥ
forefathers
hi
certainly
eṣām
of them
lupta
stopped
piṇḍa
of offerings of food
udaka
and water
kriyāḥ
performances

An increase of unwanted population certainly causes hellish life both for the family and for those who destroy the family tradition. The ancestors of such corrupt families fall down, because the performances for offering them food and water are entirely stopped.