Politicians in government and the opposition parties are blaming inter-ministry rivalry for the alleged spying episode in Finance Minister Pranab Mukherjee’s office and at 16 places in the ministry, but senior home ministry officials have a more prosaic explanation for the mysterious appearance of chewing gum: foreigners. “This is a common problem. Delegates coming for talks are often seen chewing gum and we believe they are responsible for sticking it underneath tables. We have to face similar problems sometimes,” a senior bureaucrat said.