Context: Further problems hampered the Arctic project after the commencement of drilling in 2012, as Shell dealt with a series of issues that involved air permits, Coast Guard certification of a marine vessel and severe damage to essential oil-spill equipment. Additionally, difficult weather conditions resulted in the delay of drilling during mid-2012 and the already dire situation was exacerbated by the "Kulluk" incident at the end of the year. Royal Dutch Shell had invested nearly US$5 billion by this stage of the project.

Question: What conditions caused the delay of drilling in mid-2012?
Answer: difficult weather

Question: What worsened the situation at the end of 2012?
Answer: the "Kulluk" incident

Question: What amount had Royal Dutch Shell invested in the project by the end of 2012?
Answer: nearly US$5 billion

Question: In what year did drilling in the Arctic region begin?
Answer: 2012

Question: When did the Arctic project end?
Answer: Unanswerable

Question: Who damaged essential oil-spill equipment?
Answer: Unanswerable

Question: How much was invested in the Kulluk incident?
Answer: Unanswerable

Question: What caused the Kulluk incident?
Answer: Unanswerable

Question: What certification was the Kulluk missing?
Answer: Unanswerable