On 1 May, Iran’s petrochemicals producers had one more problem to deal with. Up to now, the sector has been largely immune from the international sanctions, which have primarily targeted Iran’s oil and gas industries.

Things were tough though. Few international petrochemical firms have been willing to invest in the country, leaving the sector trying to cope on its own with an ambitious expansion plan.

But international pressure has been gradually increasing. The EU’s latest round of sanctions on 23 January broadened its existing restrictions to include the import of oil and petrochemicals, along with the export of related equipment and technology. The new trade sanctions came into effect on 1 May and also prohibit insurers from covering tankers carrying Iranian petrochemicals.

The restrictions are intended to make it difficult for all stages of petrochemical and oil trade, from finding a carrier, underwriting the sale and clearing payments. Ship owners will be reluctant to call on Iranian ports and load unless they are guaranteed full shipping insurance, covering the hull and machinery.

While previous US and UN sanctions have been criticised for being ineffectual, the latest round looks to have a lot more bite. Economic sanctions and political isolation have deeply hurt the Iranian regime. On 23 May, Iran will sit down with the five permanent members of the UN Security Council and Germany in Baghdad to negotiate the possible terms of a deal over its nuclear ambitions.

Just 15 months ago, Tehran had rejected any such talks, so the regime’s decision to re-enter discussions represents a dramatic about-turn.